JP4211925B2 - Feeding belt - Google Patents

Description

  The present invention relates to a paper feeding / conveying belt that feeds and conveys paper sheets in an electrophotographic image forming apparatus such as a printer, a copying machine, and a facsimile machine.

  Conventionally, EPDM is mainly used as a paper feeding belt for a copying machine or the like because of characteristics such as an appropriate friction coefficient and wear resistance (see, for example, Patent Documents 1 and 2).

  However, since the silicone oil adheres to the printed matter or the like formed with a color image by an electrophotographic image forming apparatus that forms a color image, the EPDM belt is used for such a color image as a manuscript or for duplex printing. There is a problem that the friction coefficient is lowered due to use over time, and trouble of conveyance failure occurs.

Japanese Patent Publication No. 7-53541 (Claims) Japanese Patent No. 3237214 (Claims etc.)

  In view of the above circumstances, it is an object of the present invention to provide a paper feeding and conveying roll made of silicone rubber having the same conveying characteristics as EPDM and having good compatibility with silicone oil.

According to a first aspect of the present invention for solving the above-mentioned problems, a belt for a sheet feeding / conveying belt used in an electrophotographic image forming apparatus for forming a color image is made of a silicone rubber having a rubber hardness of 50 ° or less and has an inner diameter. 30 mm or more and thickness is 2 mm or less, and the following formula Lumbar force (%) = [ ((2) from the amount of sink when the outer surface of the belt body is placed in contact with a horizontal base and a load is applied to the upper part. The height of the belt when a load of 40 g is applied) / ( the height of the belt when placed ) ] × 100
The bulge rate (%) of the following formula is obtained from the bulge amount of the belt body when a load of 1 kg is applied to a pair of pulleys with a predetermined diameter of 80% or less. Swelling amount (mm) / pulley outer diameter (mm)] × 100
The swell ratio represented by the formula is 12% or less.

  According to a second aspect of the present invention, in the first aspect, the belt main body is a paper feeding and conveying belt characterized in that the core body is embedded without using an adhesive.

According to a third aspect of the present invention, in the second aspect, there is provided a paper feeding / conveying belt characterized in that a knitted fabric is embedded inside as the core body.

  According to a fourth aspect of the present invention, in the third aspect, a feeding and conveying belt is characterized in that a filamentous body is embedded as the core body outside the knitted fabric.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, a belt is wound around a pair of pulleys, and one pulley is rotationally driven and rotated while a 1 kg load is applied between the pulleys. The driving torque as a starting value is 400 gf · cm or less.

  The sheet feeding / conveying belt of the present invention has an effect of providing a sheet feeding / conveying belt made of silicone rubber which has excellent conveying characteristics and is compatible with silicone oil.

  In the paper feeding / conveying belt of the present invention, the belt body is made of silicone rubber having a rubber hardness of 50 ° or less. Here, the type of the silicone rubber is not particularly limited, and may be a liquid silicone in which two liquids are mixed or a heat vulcanized silicone, but a rubber having a rubber hardness of 50 ° or less is used. When the angle is higher than 50 °, there is a problem that, as will be described later, the waist force and the bulge rate increase, and the friction coefficient decreases. In order to obtain a sufficient coefficient of friction, it is desirable that the silicone rubber has a resilience of 60% or more, more preferably 65% or more.

  The feeding and conveying belt of the present invention has an inner diameter of 30 mm or more and a thickness of 2 mm or less. This is because the lower back force described later is within a predetermined range and sufficient transport characteristics are obtained. That is, when the thickness is greater than 2 mm, the lumbar force increases and the conveyance characteristics deteriorate. For example, when the minimum torque when it is wound around a pulley and driven to rotate is measured, it rapidly increases when it exceeds 2 mm, and is not suitable for a paper feeding / conveying belt made of silicone.

  Further, the paper feeding / conveying belt of the present invention has a characteristic that the waist force is 80% or less.

  Here, the waist force is the height of the belt body (vertical outer diameter) when the belt body is placed with the outer surface of the belt body in contact with a horizontal base, and the load from the state to the upper part. The amount of sinking when the value is added (the amount of sinking from the state where the upper end in the vertical direction does not apply a load) was measured, and the following formula was obtained from these.

Waist strength (%) = [ (belt height when load 40 g is applied) / ( belt height when placed)] × 100

  Such lumbar force represents a restoring force when an external pressure is applied to the belt, and represents a difficulty in winding the pulley, and the lumbar force is preferably 80% or less. If the lumbar force is greater than 80%, a sufficient frictional force cannot be obtained when it is wound around the pulley, that is, a driving force cannot be obtained. In other words, the minimum torque required to drive the pulley around the pulley increases, so that the conveyance characteristics are deteriorated. The driving torque is shown in a test example described later. For example, the driving torque when a load of 1 kg is applied is preferably 400 gf · cm or less.

  In addition, the roll for feeding and feeding according to the present invention is installed on a pair of pulleys having a predetermined diameter, and a bulge measured from a bulge amount of the belt body when a load of 1 kg is applied to at least one of them in a direction away from each other. The rate is 12% or less.

  Here, the swelling rate is expressed by the following equation.

  Swell rate (%) = [swell amount (mm) / pulley outer diameter (mm)] × 100

  The bulging rate has a great influence on the conveyance characteristics together with the above-mentioned low-intensity force. Even when a rubber hardness of 60 ° is used, the bulging rate is 12% or less when a 2 mm-thick sheet feeding conveyance belt is used. Otherwise, sufficient transport characteristics cannot be obtained.

  The sheet feeding / conveying belt of the present invention is made of silicone rubber as described above, but does not use an adhesive even when the core body is embedded in order to have the above-described low power and swelling rate. Is preferred. This is because the use of an adhesive tends to increase the waist strength and the swelling rate. On the contrary, since it consists of silicone rubber, it has good permeability and the core body can be embedded in the belt body integrally without using an adhesive. Moreover, the merit that the load with respect to an environment is reduced by not using an adhesive agent arises.

  In the paper feeding / conveying belt of the present invention, a core body such as a woven fabric or a knitted fabric is preferably embedded on the inner side, that is, on the pulley contact side, and particularly preferably a knitted fabric is embedded as the core body. This is because it does not greatly affect the waist strength and the swelling rate.

  Moreover, it is preferable that the thread-like core body is embedded in the sheet feeding / conveying belt of the present invention in the circumferential direction. This is to ensure the durability and functionality of the belt body. The type of the thread-like core is not particularly limited as long as it is used for a general belt, but a synthetic thread such as a polyester thread or a polyamide thread or a natural thread may be used, and the thickness is, for example, 30. What is about the count is used.

  FIG. 1 shows a cross section of an example of the sheet feeding / conveying belt of the present invention. As shown in FIG. 1, a knitted fabric 12 is embedded inside a belt main body 11 made of silicone rubber, and a thread-like core body 13 is embedded outside the knitted fabric 12. A method of manufacturing such a sheet feeding / conveying belt 10 is not particularly limited. For example, a knitted fabric 12 is placed on a cylindrical mold that defines the inner diameter of the belt main body 11 and a thread-shaped core body 13 is wound thereon, and a silicone is formed thereon. It is manufactured by winding raw rubber, winding a film, and vulcanizing.

  Hereinafter, the present invention will be described based on examples and comparative examples.

(Test products 1a to 1e)
Covered with knitted fabric and wound with 30th polyester yarn, covered with a raw rubber of 40 ° silicone mold on a 41mm outer diameter mold, covered with film and vulcanized, finished thickness 1mm, 1.5mm, 2mm 2.5 mm, 3 mm, and finished, then cut to a width of 25 mm to obtain belts of test products 1a to 1e.

(Test products 2a to 2e)
The belts of test products 2a to 2e having thicknesses of 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 3 mm were obtained in the same manner as the test products 1a to 1e, except that silicone rubber having a rubber hardness of 50 ° was used.

(Test products 3a to 3e)
Belts of test products 3a to 3e having thicknesses of 1 mm, 1.5 mm, 2 mm, 2.5 mm, and 3 mm were obtained in the same manner as the test products 1a to 1e except that silicone rubber having a rubber hardness of 60 ° was used.

(Test Example 1)
As shown in FIG. 2, the height T1 (mm) when the belt of each test product is placed on a horizontal base and the height T2 (mm) when a load of 40 g is applied to the top are measured. The lower back strength (%) was obtained from the following formula. The results are shown in Table 1 and FIG.

Sinking rate (%) = [1- (T2 / T1)] × 100
Waist strength (%) = 100−sink rate (%) = (T2 / T1) × 100

  From this result, the test product 1e having a thickness of 3 mm is obtained for the 40 ° product, the test products 2d and 2e having a thickness of 2.5 mm and 3 mm for the 50 ° product, and the thicknesses of 2 mm, 2.5 mm and 3 mm for the 60 ° product. It was found that the test products 3c, 3d and 3e each had a waist strength of over 80% and were difficult to wind.

(Test Example 2)
The driving torque was measured for each test belt. That is, each belt is wound around a pair of pulleys having an outer diameter of 22 mm and an outer diameter of 12.7 mm, and one pulley is driven to rotate while a load of 1 kgf is applied between the pulleys. Torque (gf · cm) was used. The results are shown in Table 2 and FIG.

  From this result, it was found that when the thickness of the belt exceeds 2 mm, the driving torque rapidly increases and the belt is difficult to drive.

(Test Example 3)
Similarly to Test Example 2, the belt of each test product was wound between a pair of pulleys, the drive torque was increased, and the drive torque when slippage began to occur between the belt and the pulley was taken as the slip-out torque. The results are shown in Tables 3 and 4, and FIGS.

  From the results shown in Table 3 and FIG. 5, it was found that when the belt thickness exceeds 2 mm, the slip-out torque rapidly decreases, which is not preferable for use.

  Further, from the results of Table 4 and FIG. 6, it is understood that when the rubber hardness is 40 ° and 50 °, the driving torque is stable when the waist force is 80% or less, and the waist force is preferably 80% or less. It was. A sample with rubber hardness of 40 ° and a thickness of 2.5 mm has a waist strength of 80% or less, but the belt thickness exceeds 2 mm, so the driving torque increases greatly and is not suitable for actual use. Met.

(Test Example 4)
As shown in FIG. 7, the belt of each test article is wound around a pair of pulleys having a diameter of 20 mm, and a bulge amount d (mm) from the pulley diameter of the belt is measured with a load of 1 kgf applied to one pulley. The swelling rate (%) was obtained from the following formula.

  Swell rate (%) = [swell amount d (mm) / pulley outer diameter r (mm)] × 100

  The results are shown in Table 5. As a result, in the test product 2c having a belt thickness close to the limit of the use range of 2 mm and the waist strength of approximately 80%, the swelling rate is 11.8%, and the test product that was out of the use range in the above-described test. Was larger than this. Therefore, it was found that the amount of swelling is suitable for use within a range of 12% or less.

It is a cross-sectional view showing an example of a sheet feeding and conveying belt of the present invention. 6 is a diagram for explaining a measurement method of Test Example 1. FIG. 6 is a graph showing measurement results of Test Example 1. 10 is a graph showing measurement results of Test Example 2. 10 is a graph showing measurement results of Test Example 3. 10 is a graph showing measurement results of Test Example 3. 10 is a diagram for explaining a measurement method of Test Example 4. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Feeding and conveying belt 11 Belt body 12 Knitted fabric 13 Threaded core

Claims (5)

In a paper feeding / conveying belt used in an electrophotographic image forming apparatus for forming a color image, the belt body is made of silicone rubber having a rubber hardness of 50 ° or less and an inner diameter is 30 mm or more and a thickness is 2 mm or less . From the amount of sinking when the outer surface is placed in contact with a horizontal base and a load is applied to the upper part, the following formula: Lumbar force (%) = [ (belt height when a load of 40 g is applied) / ( The height of the belt when placed ) ] × 100
The bulge rate (%) of the following formula is obtained from the bulge amount of the belt body when a load of 1 kg is applied to a pair of pulleys with a predetermined diameter of 80% or less. Swelling amount (mm) / pulley outer diameter (mm)] × 100
A swell ratio represented by the formula (1) is 12% or less. 2. The sheet feeding / conveying belt according to claim 1, wherein the belt main body is embedded in the core without using an adhesive. 3. A sheet feeding / conveying belt according to claim 2 , wherein a knitted fabric is embedded inside the core body. 4. The sheet feeding and conveying belt according to claim 3, wherein a filamentous body is embedded as the core body outside the knitted fabric. The belt according to any one of claims 1 to 4, wherein a belt is wound around a pair of pulleys, one pulley is rotationally driven with a 1 kg load applied between the pulleys, and a driving torque that is a value when the pulley starts to rotate is 400 gf. A belt for paper feeding and conveyance, characterized in that it is cm or less.

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