JPH06100877B2 - Coated roll for printing machine and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a roll for a heating and pressure printing machine such as a fixing device of an electrophotographic copying machine, and particularly to a non-adhesive coating for coating the roll surface. The present invention relates to improvement of a resin layer.

[Prior Art] The electrophotographic copying machine, which is the main application of the roll of the printing machine of the present invention, disperses toner onto the latent image surface formed on the photosensitive drum 1 as shown in the outline of FIG. Is attached to the latent image to form a visible image, which is transferred to the copy paper 2. The toner image transferred to the copy paper 2 is heated by the heating roll 3
The image is fixed by being heated and melted by a fixing roll 5 composed of a pressure roll 4 and a pressure roll 4 and being pressed against the copy paper 2.

As shown in FIG. 4, the heating roll 3 has a hollow metal roll 9 as a core material, has an electric heating device 6 inside the hollow, and has a non-adhesive surface for preventing toner offset. A coating layer 7 made of a substance is provided. Silicone rubber, fluororesin such as polytetrafluoroethylene (PTFE), etc. are used as the non-adhesive substance.

In the coating layer made of such a non-adhesive substance, for example, a rubber elastic body coated on the surface of a metal roll may be mixed with metal powder, metal fibers or fiber chips to improve thermal conductivity and conductivity. What to do (Japanese Patent Publication Sho 61-34146
No.) or a metal roll surface, a heat-resistant adhesive layer, a heat-resistant oil elastic layer, a heat-resistant oil adhesive layer, and an offset prevention layer are sequentially laminated to firmly adhere the offset prevention layer and prevent the offset prevention layer from peeling. Aiming fuser roll
-60430)).

Further, as the coating method, after applying the primer to the roughened metal roll surface, apply the PFA powder and fire in the furnace, or without applying the primer,
A method (Japanese Patent Publication No. 61-41269) has also been proposed, in which PFA powder is applied and then fired, and by controlling the cooling rate after firing, the adhesion of the PFA film to the metal roll is also made tight and firm. There is.

Further, the present applicant has proposed a roll for a printing machine in which the surface of a metal roll is coated with a thermosetting resin in which powder of a solid lubricant is dispersed (Japanese Patent Application No. 1-222481, 22482).

On the other hand, the pressure roll can be obtained by a structure having no heating element of the heating roll, or the metal roll can be used as it is.

[Problems to be Solved by the Invention] In the conventional heat-fixing roll, the non-adhesive substance has a poor adhesive force with metal, and in order to compensate for this, the surface of the metal roll 9 is as shown in FIG. It is necessary to provide a coating layer 7 made of a non-adhesive substance with a heat-resistant and oil-resistant adhesive primer 8 interposed therebetween, and these resin layers are sequentially laminated (Japanese Patent Publication No.
-60430) required a complicated manufacturing process. Further, since the surface of the fired resin has an irregular shape, it was necessary to polish it to make it uniform. Also, defects may occur in the fluororesin layer,
Furthermore, even if the above-mentioned fluororesin is applied and fired once, it is possible to obtain a film thickness of at most 10 μm, and in order to secure the required film thickness, multiple application and firing steps must be performed. It was

Further, the roll for a printing machine coated with the thermosetting resin in which the powder of the solid lubricant is dispersed, the powder of the solid lubricant densely covers the surface layer of the roll and exhibits an appropriate surface roughness.
The non-adhesive oil applied to the uneven surface was contained to prevent the copy paper from wrapping around the fixing roll. But,
When the supply of non-stick oil is interrupted,
The carbon toner adhered to the printing roll, and the printing paper was eventually wrapped around. Further, recently, there are printers that do not use non-stick oil, and even a roll coated with a thermosetting resin in which the powder of the solid lubricant is dispersed is not satisfactory.

The present invention eliminates the above-mentioned complications in production, has excellent heat resistance, abrasion resistance, oil resistance and heat transfer response, and yet has a non-adhesive oil that prevents wrapping between a printing press roll and printing paper. It is intended to obtain a printing roll in which the copy paper does not wind around the roll surface even when it does not exist.

[Means for Solving the Problems] In order to solve the above problems, in the coating roll for a printing press of the present invention, the powder of the solid lubricant 11 in a state in which at least a part of the coating roll for the printing press is melted on the surface of the metal roll 9 is used. It is characterized by being coated with a thermosetting resin containing.

A second invention is a method for manufacturing a roll for a printing press, which comprises applying a thermosetting resin containing a powder of a fluororesin-based solid lubricant to the surface of a metal roll and thermally curing the same, wherein the thermosetting resin is used as the thermosetting resin. The thermosetting polymer resin containing the fluororesin solid lubricant powder is used as the film thickness.
The method for producing a coating roll for a printing machine is characterized in that the coating roll is applied in a thickness of 50 μm or less and is thermally cured at 260 to 400 ° C.

The metal roll in the present invention is preferably made of aluminum or an aluminum alloy, and may be titanium, copper, steel or the like. Aluminum alloy has heat transfer, strength,
From the viewpoints of heat resistance, corrosion resistance and weight reduction, Al-Mg-Si based alloys, JIS-A5052 and A5056 are particularly preferable.

Thermosetting resins must have strong adhesiveness with metals as well as heat resistance, abrasion resistance, and oil resistance. Polyimide resin, polyamide-imide resin, phenol resin (PF), amino resin ( Urea resin UF, Melamine resin M
F), unsaturated polyester resin (UP), epoxy resin (E
P), allyl resin (DAP), silicone (SI), polyurethane (urethane resin) (PUR), polyphenylene sulfide (PPS), furan resin, etc. are used.

Solid lubricants are polytetrafluoroethylene (PTFE), peroxyalkoxy fluororesin (PFA) tetrafluoroethylene hexafluoropropylene copolymer (FEP), ethylene in terms of wear resistance, heat resistance and oil resistance. Fluororesin systems such as ethylene tetrafluoride copolymer (ETFE), vinylidene fluoride (PVDF), polychlorotrifluoroethylene (PCTFE), vinyl fluoride (PVF) are preferred. This powder has a particle size of 10 μm
The following is preferable, and when the particle size becomes large, the binding force with the thermosetting resin decreases, and abrasion resistance cannot be obtained.

The content of the solid lubricant in the thermosetting resin is preferably 20 to 95% by weight, although it depends on the kind of the fluororesin. Particularly, PTFE is more preferably 20 to 60%, and PFA is more preferably 60 to 95%.

If the content of the solid lubricant is less than 20%, the non-adhesive effect with the toner cannot be obtained, and if it exceeds 95%, the thermosetting resin will be insufficiently bonded to the metal roll and the solid lubricant, and Peeling occurs, shortening the service life.

In the present invention, it is preferable that the metal roll is coated with the thermosetting resin in which the solid lubricant is dispersed / contained in a thickness of 50 μm or less. If the coating layer becomes thicker than 50 μm,
This is because the profile suitable for a printing machine roll on the surface of the metal roll is impaired.

[Operation] According to the present invention, as shown in FIG. 1, the surface of the metal roll is coated with the thermosetting resin 12 containing at least part of the molten solid lubricant powder 11 dispersed and contained therein. It is not necessary to interpose an adhesive primer as in the conventional case, and the polishing treatment of the resin-coated surface is not necessary.

Since the solid lubricant particles share the wear resistance, heat resistance, and oil resistance, these points are the same as those of the conventional fluorine resin coating roll.

The resin coating layer containing the solid lubricant used in the present invention dispersed therein is coated on the surface of the metal roll and then heat-cured,
Since a smooth coating layer can be formed along the fine profile on the surface of the metal roll, the subsequent polishing finish is not required as described above, and therefore the coating thickness can be reduced, and the entire printing press roll can be obtained. As a result, the thermal conductivity is good, the thermal response is good, and the fluctuation of the fixing temperature is small. Further, the solid lubricant particles are densely dispersed and the film thickness is thin, so that the compression set is small.

Further, since at least a part of the solid lubricant was melted, the toner did not adhere to the roll even without the non-adhesive oil described above, the printing paper was not wound, and the printability was good.

In the production method of the present invention, a resin having a low content of solid lubricant may be applied to the first layer on the surface of the metal roll, and the content of solid lubricant may be increased as the surface layer of the coating advances.

Since the solid lubricant has poor adhesion to metal, it is preferable to increase the amount of the thermosetting resin and to increase the amount of the fluororesin solid lubricant on the surface where abrasion resistance is required.

A coating thickness of 50 μm or less is applied and heat-cured at 260 to 400 ° C. When the coating layer is thicker than 50 μm, the profiling suitable for printing machine rolls on the surface of metal rolls is impaired. When the heat curing temperature is 260 ° C or lower, the solid lubricant does not melt and toner adheres much. At temperatures higher than 400 ° C, the solid lubricant melts and in some cases decomposes or flows. And the profile suitable for a printing machine roll on the surface of the metal roll is impaired.

[Examples] The most preferred embodiment of the present invention using aluminum as a metal roll and a polyimide resin as a thermosetting resin will be described below as an example.

[Performance Test] A1 plate having a plate thickness of 0.3 mm was spray-coated with a mixed solution of coating materials shown in Table 1 and treated under the baking conditions for curing shown in Table 1. Various tests were performed on the obtained coated plates having different film thicknesses, and the results are shown in Table 1.

Based on JIS K 5400 cross cut test, 10 x 10 cross cut scratches were made on the coated surface with a razor at 1 mm intervals, and a peel test was performed using cellophane tape. Was designated as x.

In the bending test, based on JIS K 5400, bending was performed with the coated surface facing outward at an internal bending radius of 1.5 mm and 180 °, and surface cracking and peeling were observed.

In the toluene immersion test, after immersion for 24 hours, bending was carried out in the same manner as in the bending test, and the degree of surface cracking was examined.

A reciprocating sliding type pin-on-disk tester was used for the tests of wear life and friction coefficient. The mating material was a steel ball with a diameter of 6 mm, the load was 3 kg, the speed was 240 cycles / min, and the sliding width was 10 mm.

The wear life was evaluated by the number of times of sliding until the friction coefficient reached 0.3. The coefficient of friction was evaluated by the coefficient of friction that was initially stable.

The pencil hardness test was performed based on JIS K 5400.

In the withstand voltage test, a brass weight having a bottom area of 1 cm ^{2 and} a weight of 100 g was placed on the coated surface, and electricity was applied to the base material and the weight.

[Adhesion test of carbon toner on roll surface] When a phenomenon in which the paper becomes wrapped around the roll surface during printing was investigated, first, the carbon toner adhered to the roll surface, and the carbon toner adhered to the roll surface. It was found that a part of the paper was adhered and pulled to the roll side, the paper was torn and wrapped around the roll. Therefore, in order to investigate the adhesion between the carbon toner and the roll surface, as shown in Fig. 5, carbon toner was placed on the surface of the plate coated with the coating material on the A1 plate surface, and the carbon toner was placed on the plate through the glass plate to the fixing roll. A suitable surface pressure was applied, the product was inserted into a furnace whose temperature was raised, and it was examined whether carbon toner adhered to the resin plate.

Inventive Examples Nos. 1 to 14 are cross-cut test, bending test, and toluene immersion test, and have performance comparable to Comparative Example and Conventional Example, wear life, pencil hardness, friction coefficient and withstand voltage are Comparative Examples. Equally superior in performance compared to the conventional example. Further, regarding the adhesion state of the carbon toner, the present invention materials No. 1 to 14 have the same performance as the conventional material and are superior to the comparative material. Comparative materials Nos. 15 to 25 have a curing temperature of 250 ° C.
Since the solid lubricant is not melted, the amount of carbon toner adheres a lot and the printing performance is deteriorated. Further, the conventional materials No. 26 and 27 are obtained by melting and firing the solid lubricant of the present invention and have no carbon toner adhesion, but are inferior in cross-cut test, hardness, wear life, and withstand voltage performance. It is a thing.

[Actual machine test] An actual roll was manufactured under the same manufacturing conditions as Nos. 3 and 9 shown in Table 1, and a built-in test was performed on the actual machine.

After preparing a metal roll 9 made of an aluminum alloy, cutting and finishing the surface, degreasing / cleaning, shot blasting, and preheating, and then, as a solid lubricant, an average particle diameter of 8 μm.
Of PTFE or PFA powder of 30% and 70% by weight, respectively, is applied to the surface of the aluminum alloy roll by spraying, and 400 ° C for 20 minutes at 350 ° C in an electric furnace.
The non-adhesive resin 12 was formed by heat-curing at 30 ° C. for 30 minutes, and was directly incorporated in the actual machine. The obtained coatings each had a thickness of 15 μm and a surface roughness Rz of 4 to 8 μm. The durability test of the roll of the present invention was carried out in a state where the non-stick oil incorporated in an actual machine was not used. One year later, it was taken out of the actual machine and visually inspected for peeling of the film and adhesion of toner, and it was confirmed that there was no abnormality.

The actual roll coating 10 is composed of a polyimide resin 12 containing a fluorine resin powder 11 of a solid lubricant on a metal surface made of an aluminum alloy. Fluororesin-based powder of solid lubricant is partially dispersed in polyimide resin in a semi-molten state and is exposed in the surface layer, which increases wear resistance, and the surface layer becomes denser and forms minute irregularities. In fact, the copy sheet is prevented from being wound around the fixing roll between the copy sheet and the fixing roll. In addition, the interface between the aluminum alloy and the resin layer was rich in polyimide resin, strengthened the adhesive force with the metal, prevented the peeling of the coating layer, and had the effect of life.

As a comparative example, an actual roll was manufactured under the same manufacturing conditions as the sample No. 15 shown in Table 1 and incorporated in an actual machine that does not use non-adhesive oil for testing. As a result, one day after the start, the carbon toner adhered and the paper came to wrap around.

[Effects of the Invention] The present invention has the following effects.

Since the solid lubricant is dispersed and contained in the thermosetting resin, it is not necessary to interpose a primer layer unlike the conventional fluororesin film, and the film thickness can be reduced.

Since the coating can be formed by heating and curing the resin after spray coating, it can be used without polishing.

The coating has excellent wear resistance and can extend the service life of the roll.

Since the film thickness is thin, it has excellent thermal conductivity and good thermal response. Further, the fluctuation of the fixing temperature is small.

Since the film thickness is thin, the permanent compression deformation is small.

The powder of the solid lubricant densely covers the surface layer portion, has an appropriate surface roughness, prevents the copying paper from being wound around the fixing roll, and improves the printability.

Since at least a part of the solid lubricant was melted, the carbon toner did not adhere to the roll even without the non-adhesive oil described above, the printing paper was not wrapped around, and the printability was good.

Although the above description has been directed to the heat fixing roll, the roll of the present invention can also be used as a pressure roll by adopting a structure having no heating element. Needless to say, it can be used for printing rolls such as printers.

[Brief description of drawings]

FIG. 1 is a sectional view illustrating an embodiment of the present invention, FIG. 2 is a sectional view illustrating a comparative example, FIG. 3 is an explanatory view of an electrophotographic copying machine, and FIG. 4 is a sectional view illustrating a heating roll. FIG. 5 is a diagram for explaining the adhesion test of the toner on the roll surface. 1 ... Photosensitive drum, 2 ... Copy paper, 3 ... Heating roll, 4 ... Pressure roll, 5 ... Fixing roll, 6 ... Heating device, 7 ... Covering layer, 8 ... Adhesive primer, 9 ...... Metal roll, 10 …… Resin film containing and containing solid lubricant, 11 …… Solid lubricant powder, 12 …… Polyimide resin.

Claims (2)

[Claims] 1. A printing machine, characterized in that the surface of a metal roll is coated with a thermosetting resin containing at least a part of a powder of a fluororesin solid lubricant in a melted state. Coating roll. 2. A method for producing a roll for a printing press, comprising applying a thermosetting resin containing a powder of a fluororesin-based solid lubricant to the surface of a metal roll and thermally curing the same, wherein the thermosetting resin is the thermosetting resin. 2. A coating roll for a printing press according to claim 1, wherein a thermosetting resin containing a fluororesin-based solid lubricant powder is used, and a coating thickness of 50 .mu.m or less is applied to the coating roll, and the coating roll is thermoset at 260 to 400.degree. Production method.