JP7726780B2 - Cleaning roll and method for manufacturing cleaning roll - Google Patents

Description

This disclosure relates to a cleaning roll and a method for manufacturing the cleaning roll.

Conventionally, cleaning rolls used in devices such as copiers and printers, and in the toner cartridges installed in these devices, are known (see, for example, Patent Documents 1 and 2). The cleaning roll in Patent Document 1 comprises a shaft member and a foam body attached around the shaft member. The foam body of the cleaning roll rotates in accordance with the rotation of the charge roll while in contact with the charge roll. In this way, the cleaning roll removes residual toner and foreign particle particles adhering to the surface of the charge roll by contacting the foam body with the charge roll.

There are various methods for manufacturing such cleaning rolls. One example of a method for manufacturing a cleaning roll is a method in which a foam is attached to a shaft member and then the foam is carved to form a cylindrical shape, as in the cleaning roll of Patent Document 1. Another example of a method for manufacturing a cleaning roll is a method in which a sheet containing a foam is wrapped around a shaft member, as in the cleaning roll of Patent Document 2.
Patent Publication No. 2021-18292 Patent Publication No. 2011-145410

In recent years, there has been a demand for improved durability in devices such as copiers and printers. This has led to a demand for cleaning rolls with even greater durability and the ability to manufacture such cleaning rolls.

It is also preferable for the foam surface of the cleaning roll to adhere closely to the charging roll. For this reason, there is a demand for cleaning rolls with smaller outer diameter tolerances and for the manufacturing of such cleaning rolls.

The objective of this disclosure is to provide a new cleaning roll that is highly durable and has a small outer diameter tolerance, as well as a method for manufacturing the cleaning roll.

The cleaning roll according to the present disclosure comprises a shaft member and a sheet formed in a band shape and containing a foam, which is wound around the shaft member in the axial direction. The foam includes first cells, and the first cells have bent portions that bend inward toward the inside of the first cells.

The method for manufacturing a cleaning roll according to the present disclosure also includes a compression step of compressing the foamed foam, a step of forming the foam into a strip-shaped sheet, and a step of wrapping the sheet around a cylindrical shaft member in the axial direction.

With this cleaning roll, the foam is compressed, resulting in a high foam density. This makes the cleaning roll more durable than conventional cleaning rolls. Furthermore, with this cleaning roll manufacturing method, the compressed foam is wound around the shaft, which reduces deformation of the foam when it is wound around the shaft. As a result, cleaning rolls manufactured using this cleaning roll manufacturing method have a smaller outer diameter tolerance than conventional cleaning rolls.

This disclosure provides a new cleaning roll with high durability and narrow outer diameter tolerance, as well as a method for manufacturing the cleaning roll.

FIG. 2 is a side view of a cleaning roll according to an embodiment of the present disclosure. FIG. 2 is a front view of a cleaning roll according to an embodiment of the present disclosure. FIG. 2 is a schematic diagram of a sheet according to an embodiment of the present disclosure before being attached to a shaft member. 2 is a photograph showing the state of the cross section AA in FIG. 1. Photographs showing the change in cross section of a foam when the compression ratio is changed. FIG. 4 is a schematic diagram showing changes in first cells and second cells of a foam when the compression rate is changed. 1A to 1C are diagrams illustrating a manufacturing procedure according to an embodiment of the present disclosure. A diagram showing the outer diameter tolerance.

<Structure of cleaning roll>
An embodiment of the present disclosure will be described below with reference to the drawings. As shown in FIGS. 1 to 3, a cleaning roll 1 includes a shaft member 2 and a sheet 4. The cleaning roll 1 of this embodiment is attached to a toner cartridge used in a laser printer or a copier. The cleaning roll 1 is attached to the charging roll of such a cartridge with the foam surface of the cleaning roll 1 in contact with the charging roll.

In recent years, there has been a trend toward longer lifespans for such cartridges. For this reason, the cleaning roll 1 that comes into contact with the charging roller must be durable enough to prevent damage to the foam surface of the cleaning roll 1. Furthermore, in recent years, there has been a trend toward smaller cartridges. For this reason, there is also a demand for smaller cleaning rolls 1.

In this embodiment, the shaft member 2 is a columnar or cylindrical rod made of metal or the like. In this embodiment, the diameter D1 of the shaft member 2 is 3.0 mm to 4.0 mm. The length of the shaft member 2 is generally 226 mm to 350 mm. However, the diameter and length of the shaft member 2 can be set appropriately depending on the device to which the cleaning roll 1 is attached.

The sheet 4 is formed in a strip shape including a foam 6 and an adhesive layer 8, and is spirally wound around the outer peripheral surface of the shaft member 2 along the axial direction F of the shaft member 2. In this embodiment, the foam 6 is a compressed flexible polyurethane foam. Specifically, the foam 6 is a flexible polyurethane foam obtained by compressing a flexible polyurethane foam having an apparent density according to JIS K 6401 of 30 kg/ ^m3 to 100 kg/ ^m3 so that the apparent density according to JIS K 6401 is 100 kg/ ^m3 or more. More preferably, the foam 6 is a flexible polyurethane foam obtained by compressing a flexible polyurethane foam having an apparent density according to JIS K 6401 of 70 kg/ ^m3 at a compression rate of 30% or more so that the apparent density according to JIS K 6401 is 140 kg/ ^m3 or more.

The thickness of the foam 6 after compression is 1.0 mm to 4.0 mm, and more preferably 3.0 mm or less. The foam 6 of this embodiment is a soft polyurethane foam that has a thickness of 2.0 mm to 2.7 mm before compression and is compressed to a thickness of 1.0 mm. Therefore, if the diameter D1 of the shaft member 2 is 4.0 mm, the standard diameter D2 of the cleaning roll 1 of this embodiment is 6.0 mm.

Furthermore, the foam 6 of this embodiment is compressed by heat press molding, in which heat is applied while pressing. In this way, compressing the foam 6 while applying heat causes the foam 6 to plastically deform. This makes it possible to prevent the foam 6 from returning to its original shape after compression.

In other words, the following inventions can also be understood from the description in this specification.

A shaft member;
a sheet containing a foam, formed in a strip shape, and wound around the shaft member at a predetermined angle along the axial direction;
Equipped with
The cleaning roll has an apparent density of the foam of 100 kg/m ³ or more.

Figure 4 is a photograph of the A-A cross section of Figure 1 taken with a microscope. As shown in the circled area in Figure 4, the foam 6 formed in this manner includes first cells 10 and second cells 12. The first cells 10 have bent portions 10a that bend toward the inside of the first cells 10. The second cells 12 are adjacent to the first cells 10 and have protrusions 12a that protrude toward the bent portions 10a. Of the multiple cells formed in the foam 6, only some of the first cells 10 and second cells 12 may have the shapes of the first cells 10 and second cells 12.

FIG. 5 shows photographs taken with a microscope showing the change in the cross section of foam 6 when the compression ratio of foam 6 is changed. FIG. 5(a) shows the foam 6 in an uncompressed state. FIG. 5(b) shows the foam 6 in a compressed state at a compression ratio of 50%. FIG. 5(c) shows the foam 6 in a compressed state at a compression ratio of 57%. All foams are soft polyurethane foams with an apparent density of 70 kg/ ^m3 according to JIS K 6401. The compression ratio is the rate at which the length of foam 6 in the thickness direction H is reduced. For example, when the length of foam 6 is reduced from 6.0 mm to 3.0 mm, the compression ratio is 50%.

As shown in Figure 5(a), when the foam 6 is not compressed, multiple rugby ball-shaped cells are formed that are long in the thickness direction H of the sheet 4. Figure 6 is a schematic diagram showing the state in which these rugby ball-shaped cells shrink. In the foam 6, adjacent first cells 10 and second cells 12 are arranged so that they overlap in the thickness direction H. In other words, when the foam 6 is wrapped around the shaft member 2, the first cells 10 and second cells 12 are arranged so that they overlap in a direction perpendicular to the axial direction F in a cross section perpendicular to the axial direction F.

As shown in Figure 6(b), when the foam 6 is compressed, the first cells 10 are crushed toward the second cells 12, and the cell walls between the first cells 10 and the second cells 12 are pressed toward the inside of the first cells 10. This causes the cell walls to deform toward the inside of the first cells 10, forming bent portions 10a. Therefore, whether or not a bent portion 10a exists can be determined by whether or not the cell walls between the first cells 10 and the second cells 12 are pushing toward the inside of the first cells 10. When viewed in the photograph of Figure 5(b), this state appears as the circled area.

At this time, the second cell 12 also shrinks in the thickness direction H. As a result, the second cell 12 forms a protrusion 12a that protrudes toward the first cell 10. Therefore, the criterion for determining the protrusion 12a is whether the width X of the second cell 12 decreases toward the bent portion 10a of the first cell 10, as shown in Figure 6(b).

As shown in Figure 6(c), as compression continues, the first cell 10 and the second cell 12 shrink in the thickness direction H. Furthermore, the width X of the second cell 12 in the thickness direction H becomes smaller. Note that either or both of the first cell 10 and the second cell 12 may become completely crushed. In particular, the crushed state of the second cell 12 can be seen as the circled area in the photograph of Figure 5(c).

3, the adhesive layer 8 is a layer provided between the foam 6 and the shaft member 2. The adhesive layer 8 may be made of any material, such as an adhesive agent or adhesive tape, as long as it is capable of adhering the foam 6 to the shaft member 2.
<Method of manufacturing a cleaning roll>
Next, a manufacturing procedure (method) for the cleaning roll 1 of this embodiment will be described with reference to FIG.

As shown in Figure 7(a), first, a foam 6 having an apparent density of 30 kg/ ^m3 to 100 kg/ ^m3 according to JIS K 6401 is prepared. In this embodiment, Liquid A, which is mainly made of isocyanate, and Liquid B, which is mainly made of polyol, are mixed on a belt conveyor or in a foaming mold, and a block of polyurethane foam is prepared by foaming and curing.

As shown in Figure 7(b), the block is then sliced to a predetermined thickness to form the foam 6 into a sheet. The slice thickness may be changed as appropriate depending on the compression rate and the thickness of the foam 6 after compression. For example, if a sheet 4 with a thickness of 3.0 mm is produced at a compression rate of 50%, the slice thickness may be set to 6.0 mm.

As shown in Figure 7(c), the sheet-like foam 6 is then placed in a press 14. The press 14 can compress the foam 6 while heating it. The press 14 compresses the foam 6 at a compression rate of 30% or more. The compression rate can be set appropriately between 30% and 80%, depending on the target apparent density and thickness of the foam 6 after compression.

Once the compression process is complete, an adhesive layer 8 is formed on the foam 6. In this embodiment, an adhesive sheet is attached to the foam 6. Then, as shown in Figure 7(d), the foam is cut to a predetermined width and length to form a strip-shaped sheet 4. In this embodiment, the sheet 4 is cut to a width of 7.0 mm and a length of 400 mm. However, the width and length of the sheet 4 may be changed as appropriate depending on the length of the shaft member 2 and the proportion of the outer circumferential surface of the shaft member 2 that the sheet 4 covers.

As shown in Figure 7(e), the sheet 4 is then wrapped around the shaft member 2 at a predetermined angle α along the axial direction. The predetermined angle α varies depending on factors such as the percentage of the outer peripheral surface of the shaft member 2 that the sheet 4 covers. In this embodiment, the sheet 4 is wrapped around the shaft member 2 so that the sheet 4 covers 90% or more of the outer peripheral surface of the shaft member 2. In other words, the sheet 4 is wrapped around the outer peripheral surface of the shaft member 2 without any gaps. In this case, the predetermined angle α is preferably between 45 and 60 degrees.

In the process of winding the sheet 4 around the shaft member 2, the shaft member 2 is rotated at a predetermined rotational speed while the end 4a of the sheet 4 is moved along the axial direction F in the winding direction R at a predetermined moving speed. This causes the shaft member 2 to wind up the sheet 4. The relationship between the predetermined rotational speed and the predetermined moving speed varies depending on the diameter of the shaft member 2, the material of the sheet 4, etc.

Such a cleaning roll 1 has high durability because the foam 6 is compressed, increasing its apparent density according to JIS K 6401. For example, according to the inventors' findings, when polyurethane foam is hot-pressed, the tensile strength, elongation, and tear strength of the foam 6 according to JIS K 6401 are improved compared to when the foam 6 is not compressed. Furthermore, the improvement in durability is significant when the compression rate is 70% or higher.

Furthermore, the cleaning roll 1 reduces the thickness of the sheet 4 by compressing the foam 6. This allows the diameter D2 (see Figure 2) of the cleaning roll 1 to be smaller than when the foam 6 is wound around the shaft member 2 without being compressed. As a result, the cleaning roll 1 is smaller and more durable than conventional cleaning rolls.

In addition, conventional cleaning rolls, in which a foam-containing sheet 4 is wrapped around a shaft member, have a low density and are thick, making the center of the sheet prone to deformation and denting. However, in the cleaning roll 1 of the present disclosure, the foam 6 is compressed, increasing its density and reducing its thickness. This reduces deformation of the center of the sheet 4 when it is wrapped around the shaft member 2. As a result, the cleaning roll 1 can be manufactured with a small outer diameter tolerance. Here, the outer diameter tolerance refers to a value related to the variation in the diameter (outer diameter) D2 of the cleaning roll 1. Specifically, as shown in Figure 8, variation in the distance T from the deepest position B of the recess 6a formed on the surface of the foam 6 to the shaft surface causes variation in the diameter D2 of the cleaning roll 1. This variation can be obtained by measuring the diameter D2 of the cleaning roll 1 while rotating the cleaning roll 1. The outer diameter tolerance is the value of the diameter D2 plus or minus 3σ standard deviation when the diameter D2 is measured at multiple points on the same cleaning roll 1 or on different cleaning rolls 1 while the cleaning roll 1 is rotated.

For example, as shown in Table 1, the inventors compressed three polyurethane foams, each having an apparent density according to JIS K 6401 of 70 kg/ ^m3 and a thickness of 2.0 mm (Example 1), 2.35 mm (Example 2), and 2.7 mm (Example 3), to 1.0 mm by hot press molding, and wound the foam around a 4.0 mm shaft member 2 to create cleaning rolls 1. Five cleaning rolls 1 were created for each of Examples 1 to 3. The inventors obtained the standard deviation σ of the diameter D2 of each of Examples 1 to 3. As a result, the standard deviation σ of the diameter D2 of the five cleaning rolls 1 for each Example was 0.032 mm for Example 1, 0.036 mm for Example 2, and 0.041 mm for Example 3. Meanwhile, the inventors prepared a cleaning roll by winding a polyurethane foam having an apparent density according to JIS K 6401 of 70 kg/m ³ and a thickness of 2.35 mm around a 4.0 mm shaft member 2, as shown in the comparative example in Table 1. Five cleaning rolls of the comparative example were prepared, similar to the cleaning rolls 1 of each example. As a result, the standard deviation σ of the diameter D2 of the cleaning roll of the comparative example was 0.111 mm. Therefore, the standard deviation σ of the cleaning rolls 1 of all examples 1 to 3 was smaller than that of the comparative example, and the variation was smaller. In this way, the inventors discovered that a cleaning roll 1 with a small outer diameter tolerance could be manufactured by compressing the foam 6.

Furthermore, in a cleaning roll such as that of Patent Document 1, in which a foam is attached to a shaft member and then polished to form the foam shape, if the thickness of the foam is made thin (for example, 3.0 mm or less), the shaft member becomes visible through the foam, resulting in a problem in appearance quality. However, according to the cleaning roll 1 and the manufacturing method for the cleaning roll 1 of the present disclosure, the foam 6 is wound around the shaft member 2 in a compressed state. This increases the density of the foam 6, and the shaft member 2 does not become visible through the foam.

As described above, a novel cleaning roll 1 having high durability and small outer diameter tolerance, and a manufacturing method for the cleaning roll 1 can be provided.
<Other Embodiments>
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the spirit of the invention.

For example, in the above embodiment, the foam 6 is described as being made of soft polyurethane foam, but the present disclosure is not limited to this. The foam 6 may be made of a material other than soft polyurethane, as long as it is made of compressed elastic foam.

In this embodiment, the foam 6 is compressed and then formed into a strip-shaped sheet 4, but the present disclosure is not limited to this. The compression process may also be performed after the strip-shaped sheet 4 is formed.

1: cleaning roll, 2: shaft member, 4: sheet, 4a: end portion, 6: foam, 6a: recess, 8: adhesive layer, 10: first cell, 10a: bent portion, 12: second cell, 12a: protrusion, 14: press machine, F: axial direction, H: thickness direction, R: direction, α: angle

Claims (7)

A shaft member;
a sheet containing polyurethane foam, formed in a strip shape, and wound around the shaft member in the axial direction;
Equipped with
the foam includes first cells;
the first cell has a bent portion bent toward the inside of the first cell,
The sheet is wound around the outer peripheral surface of the shaft member so that no gap is formed between adjacent sheets in the width direction of the sheet . the foam has second cells adjacent to the first cells;
the second cell includes a protrusion protruding toward the bent portion,
The cleaning roll for a charging roll according to claim 1 . In the foam, in a cross section perpendicular to the axial direction of the shaft member, the bent portions of the first cells and the protruding portions of the second cells are arranged to overlap in a direction perpendicular to the axial direction.
The cleaning roll for a charging roll according to claim 2 . The apparent density of the foam is 100 kg/m ³ or more.
The cleaning roll for a charging roll according to any one of claims 1 to 3. a compressing step of compressing the foam-molded polyurethane foam;
forming the foam into a strip-shaped sheet;
a step of winding the sheet along the axial direction of a shaft member;
The method for manufacturing a cleaning roll for a charging roll according to claim 1 , comprising: In the compressing step, the foam is compressed while being heated.
The method for producing a cleaning roll for a charging roll according to claim 5 . providing a foam having an apparent density of 50 kg/ ^m3 to 100 kg/ ^m3 ;
In the compressing step, the foam is compressed at a compression rate of 30% or more.
The method for producing a cleaning roll for a charging roll according to claim 5 or 6.