JP7632541B2 - Refillable liquid storage tank, image forming apparatus - Google Patents

Description

This disclosure relates to a refillable liquid storage tank that can be replenished with liquid, and an image forming device that includes this refillable liquid storage tank.

Conventionally, inkjet printers are known that are equipped with a liquid storage tank that stores liquid such as ink, and consume the liquid stored in the liquid storage tank. As a liquid storage tank, a refill type liquid storage tank that can be appropriately replenished with liquid is known (see, for example, Patent Document 1).

JP 2018-161851 A

Inkjet printers require that a meniscus be formed in the ink at the tip of the nozzle by applying back pressure, or negative pressure, to the ink in the liquid storage tank to prevent ink from leaking out of the nozzle when ink is not being ejected. A differential pressure valve is provided as a means for applying back pressure to the ink in the liquid storage tank. This differential pressure valve opens and closes depending on 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 the differential pressure valve.

However, this differential pressure valve is placed in the middle of the ink supply system that supplies ink from the liquid storage tank to the nozzles. This poses the problem of increasing the size of the entire ink supply system.

This 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 an increase in the size of the liquid supply system, and an image forming apparatus equipped with this replenishment type liquid storage tank.

The refillable liquid storage tank according to the present disclosure is a liquid storage tank capable of being refilled with liquid, and is provided with a tank main body into which liquid is refilled, and a back pressure applying member that is made of an absorbent that absorbs liquid and applies back pressure to the liquid in the tank main body, and is characterized in that the tank main body has an upper limit indicator that indicates the liquid level 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 indicator.

The image forming device according to the present disclosure is characterized by being equipped with the refillable liquid storage tank according to the present disclosure.

According to the present disclosure, at least a portion of the back pressure applying member is located above the upper limit indicator. Therefore, the absorbed liquid is unlikely to reach the portion of the back pressure applying member located above the upper limit indicator, and therefore a portion of the back pressure applying member where no liquid has been absorbed can be formed. 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 its liquid absorption function, and sufficient back pressure can be applied to the liquid. In addition, a back pressure applying member made of an absorber has a much simpler configuration than a differential pressure valve. Therefore, a back pressure applying member made of such an absorber can avoid the liquid supply system from becoming larger.

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. FIG. 1 is a diagram illustrating an example of the configuration of an image forming apparatus according to the present disclosure. FIG. 13 is a schematic diagram showing a modified example of the back pressure applying member according to the present disclosure. FIG. 1 is a schematic diagram showing a modification of a refill-type liquid storage tank according to the present disclosure; FIG. 2 is a schematic diagram showing a modified example of the replenishment type liquid storage tank according to the present disclosure; FIG. 3 is a schematic diagram showing a modified example of the replenishment type liquid storage tank according to the present disclosure; FIG. 4 is a schematic diagram showing a modification of the refill-type liquid storage tank according to the present disclosure;

An embodiment of the present disclosure will be described below 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 by a partition wall 4 into an ink storage section 5 and a back pressure applying member accommodating section 6. 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 a 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.

The partition wall 4 is provided at the boundary between the ink storage section 5 and the back pressure application member storage 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 section of the ink storage section 5 and the lower section of the back pressure application member storage section 6 communicate with each other through the gap 4a formed by the partition wall 4. The gap 4a is provided at least below the convex section 2L indicating the upper limit indication section UL, which will be described later. In other words, the ink storage section 5 and the back pressure application member storage section 6 communicate with each other through the gap 4a provided below the convex section 2L indicating the 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.

The ink storage tank 1 also includes an auxiliary absorber 7. The auxiliary absorber 7 is arranged so that it flows through the gap 4a formed by the partition 4 into both the ink storage section 5 and the back pressure application member storage section 6. 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 functions to promote the movement of ink from the ink storage section 5 to the back pressure application member storage section 6.

The ink storage tank 1 also has an ink inlet 8. This allows the ink storage tank 1 to be appropriately replenished with ink, which is an example of a liquid, inside the tank main body 2 via the ink inlet 8. In other words, the ink storage tank 1 is configured as a refill-type ink storage tank that can replenish ink from the outside to the inside. The ink inlet 8 is an example of a liquid inlet.

The ink inlet 8 is provided in the upper wall 2a of the tank body 2. In this case, the ink inlet 8 is provided in the bottom wall 2a2 of the upper wall 2a of the tank body 2, which constitutes the upper wall of the ink storage section 5. The ink inlet 8 also penetrates the upper wall 2a of the tank 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 body 2, that is, into the tank body 2, more specifically, into the ink storage section 5. The ink inlet 8 also has an upper end protruding upward from the upper wall 2a of the tank body 2. The ink storage tank 1 also has a detachable cap 8a that can seal the ink inlet 8.

The ink storage tank 1 also has an air vent 9. In this case, the air 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 air vent 9 is an opening that allows air to circulate between the inside and outside of the tank main body 2.

In addition, the ink storage tank 1 is set 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 composed of the protrusion 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 protrusion protruding from the side wall 2c, but may be, for example, a recess recessed in the side wall 2c, or a label printed directly on the side wall 2c or a sticker affixed 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 is a structure that 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. The upper limit indicator UL is set at a position at least higher than the vertical center of the tank body 2. The upper limit indicator UL is set at a position at least the same as the bottom end of the ink inlet 8, or lower than the bottom end of the ink inlet 8.

The ink storage tank 1 also has 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 housing portion 6. The recording head 11 also has 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.

Next, a specific example of the configuration of the back pressure applying member 3 described above will be described. The back pressure applying member 3 is made of an absorbent capable of absorbing liquid, in this case, ink. Any suitable means capable of absorbing ink, such as a sponge, a spongy body, or a bundle of capillaries, can be used as the absorbent constituting the back pressure applying member 3. 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. In other words, the back pressure applying member 3 absorbs ink from its lower part, and the absorbed ink permeates the back pressure applying member 3 from the bottom to the top.

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 part 2 where the ink inlet 8 is provided, in this case the lower 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.

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

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 part 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 detachable, or may be an apparatus in which the ink storage tank 1 is non-detachable. 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.

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 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 the ink supply system from the ink storage tank 1 to the nozzles of the recording head 11 becoming larger.

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

In addition, with the ink storage tank 1, the top of the back pressure applying member 3 is located above the bottom 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 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.

In addition, with 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 located. Therefore, even if ink is replenished into 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.

In addition, with the ink storage tank 1, the top 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 where the ink inlet 8 is located. Therefore, even if ink is replenished into 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.

In addition, according to the ink storage tank 1, the inside of the tank main body 2, where the ink is replenished, is divided by the partition wall 4 into an ink storage section 5 and a back pressure application member storage 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 storage section 6 from the ink storage section 5 side. In addition, within the tank main body 2, the ink storage section 5 and the back pressure application member storage section 6 are in communication through the gap 4a formed by the partition wall 4. Therefore, even with the partition wall 4 in place, the ink can move smoothly from the ink storage section 5 to the back pressure application member storage section 6 without being impeded.

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

Note that this disclosure is not limited to the above-described embodiment, and various modifications and extensions are possible without departing from the spirit of the disclosure.

That is, as shown in FIG. 3, the shape of the upper part of the back pressure applying member 3 can be various shapes. 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.

Also, as shown in FIG. 4, the ink inlet 8 may be an inlet that does not protrude downward from the upper wall portion 2a of the tank body portion 2. In this case, it is preferable to configure the upper portion of the back pressure applying member 3 to be located above the lower end of the ink inlet 8.

Also, as shown in FIG. 5, the cap 8a may be a plug-in 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.

Also, as illustrated in FIG. 6, the air vent 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.

As shown in FIG. 7, the ink tank 1 may not have a partition wall 4. In this case, the back pressure member 3 may be provided in the portion where the ink storage section 5 was formed in the above embodiment. In this case, the upper portion of the back pressure member 3 is stepped, having a high portion 3a1 and a low portion 3a2 that is lower than the high portion 3a1. Therefore, the upper limit indicator UL should be provided at least above the low portion 3a2 of the back pressure member 3. In this case, the ink inlet 8 should be provided so as to be in a non-contact state with the back pressure member 3. In this case, the ink tank 1 may not have an auxiliary absorber 7. In this case, the air vent 9 may be provided in the high wall portion 2a1 that constitutes the back pressure member storage section 6 of the upper wall portion 2a of the tank main body 2.

When the ink storage tank 1 is configured with a partition wall 4, it is preferable to provide the air communication port 9 in the low wall portion 2a2, not in the high wall portion 2a1. When the ink storage tank 1 is configured without a partition wall 4, it is preferable to provide the air communication port 9 in the high wall portion 2a1, not in the low wall portion 2a2. The most preferable position for the air communication port 9 is in the low wall portion 2a2 when the ink storage tank 1 is configured with a partition wall 4.

The back pressure applying member 3 may be configured to be composed of multiple back pressure applying blocks. In this case, by making the liquid absorption performance of the multiple 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 also preferable to make the liquid absorption performance of the back pressure applying blocks arranged lower higher and the liquid absorption performance of the back pressure applying blocks arranged higher lower. This makes it easier to form a portion in the upper part of the back pressure applying member 3 that is less likely to absorb liquid, and prevents the liquid from penetrating the entire back pressure applying member 3, in other words, preventing the back pressure applying function of the back pressure applying member 3 from being reduced or lost.

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 (7)

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. 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. The refillable liquid storage tank according to claim 2 , wherein the upper limit indicator has a linear structure. 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. 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. The refillable liquid storage tank according to claim 5 , further comprising a detachable cap capable of sealing the liquid inlet. 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