Gradient dispersion composite transfer printing roller

Abstract

The invention belongs to the technical field of printing equipment manufacturing, and particularly relates to a gradient dispersion composite transfer printing roller which comprises a metal shaft core and a composite rubber tube layer wrapping the outer side wall of the metal shaft core, and is characterized in that the composite rubber tube layer sequentially comprises a base body layer, a gap layer, a transition layer and a surface layer from inside to outside in the radial direction; a micro-channel is arranged in the gap layer in the radial direction; through a radial four-layer gradient structure design, namely, a matrix layer, a gap layer, a transition layer and a surface layer, and combination with a double-helix conductive network and a micro-channel system, a gradient co-extrusion and microwave vulcanization process is cooperated, so that breakthrough improvement of resistance stability and heat dissipation efficiency is realized, and stable conductivity can be maintained when the peak temperature exceeds 138 DEG C; the improved transfer printing roller is particularly suitable for high-speed printing equipment, and the service life of the improved transfer printing roller can be several times that of a traditional product.

Description

Technical Field

[0001] The present invention relates to the technical field of printing equipment manufacturing, and particularly relates to a gradient dispersion composite transfer roller. Background Art

[0002] A transfer roller is a key component used in processes such as printing, coating, and hot stamping. It is usually made of materials such as metal and rubber, has high wear resistance and corrosion resistance, and often operates at high voltages and temperatures. In the printing industry, the transfer roller is used in the printing part of a printing press to transfer ink onto the printing material by contacting the printing plate, thereby forming patterns or characters.

[0003] Currently, the existing transfer roller made of a foamed rubber tube of nitrile rubber added with a conductive agent, although this transfer roller is made by adjusting the ratio of the conductive agent to the rubber for foaming and adjusting its resistance. However, under high constant current and high-speed use, the current causes changes in its internal molecular structure and ionic hindrance, and the resistivity will continuously increase, and finally a stable resistance cannot be achieved. Summary of the Invention

[0004] The purpose of the present invention is to provide a gradient dispersion composite transfer roller to solve the problems raised in the background art.

[0005] To achieve the above purpose, the present invention provides the following technical solution: A gradient dispersion composite transfer roller, including a metal shaft core and a composite rubber tube layer coated on its outer side wall, characterized in that the composite rubber tube layer sequentially includes a matrix layer, a void layer, a transition layer, and a surface layer from the inside to the outside along the radial direction; micro-channels are radially arranged in the void layer;

[0006] The composite rubber tube layer is prepared by the following steps:

[0007] Ingredient preparation: Weigh 100 parts of nitrile rubber, 20 parts of chlorinated ether rubber, 6 parts of ionic conductive agent, 70 - 90 parts of filler, 3 - 6 parts of accelerator, and 5 - 7.5 parts of foaming agent by weight, and seal for later use;

[0008] Rubber mixing: Mix the nitrile rubber and chlorinated ether rubber until 80°C ± 5°C, and keep it for 5 - 8 minutes. After adding the conductive agent and the filler, raise the temperature to 130°C ± 5°C and mix for 20 - 30 minutes;

[0009] Extrusion foaming: After cooling the mixed rubber for 24 hours, perform extrusion foaming at an extrusion flow rate of 4.5 - 6 and a foaming speed of 4, and the temperature gradient is 180°C - 220°C;

[0010] Gradient co-extrusion: Simultaneously form the matrix layer, the void layer, the transition layer, and the surface layer, and the temperature of the co-extrusion die head is distributed in a layer gradient of 180°C → 220°C;

[0011] Cutting and vulcanization: Cut the foamed tube to the length of the transfer roller and vulcanize it at 150 °C for 1 hour.

[0012] For the gradient heat-dissipating composite transfer roller of the present invention, the matrix layer is a nitrile rubber layer containing silver-plated glass fibers, with a thickness of 4.5 ± 0.2 mm and a volume resistivity ≤ 10 2 Ω·cm;

[0013] The void layer has a porosity of 40 ± 2% and the microchannels are radially embedded therein;

[0014] The transition layer contains Al 2 O 3 fibers and is a nitrile rubber layer coated with carbon nanotubes, with a thickness of 1.0 ± 0.1 mm and an axial thermal conductivity ≥ 12 W / mK;

[0015] The surface layer is a nitrile rubber layer containing vertically oriented carbon nanotubes and boron nitride nanosheets, with a thickness of 0.5 ± 0.05 mm and a surface resistivity ≤ 10E+0.7 Ω·cm.

[0016] For the gradient heat-dissipating composite transfer roller of the present invention, the microchannels are prepared by the following process:

[0017] Use a 355 nm ultraviolet laser to engrave the void layer radially from the inside to the outside, and the engraving parameters are a pulse energy of 50 μJ and a scanning speed of 2 m / s.

[0018] For the gradient heat-dissipating composite transfer roller of the present invention, the rubber mixing step specifically includes: Mix nitrile rubber and chloromethyl ether rubber to 80 °C ± 5 °C, keep it for 5 - 8 minutes, and add a conductive agent and a filler under a 1.5 T vertical magnetic field, then heat it up to 130 °C ± 5 °C and mix for 20 - 30 minutes while applying a 10 kHz ultrasonic vibration.

[0019] For the gradient heat-dissipating composite transfer roller of the present invention, the cutting and vulcanization step specifically includes:

[0020] Cut the foamed tube to the length of the transfer roller and vulcanize it in a 2.45 GHz microwave field at 150 °C for 1 hour, and simultaneously perform Al 2 O 3 atomic layer deposition.

[0021] For the gradient heat-dissipating composite transfer roller of the present invention, during the simultaneous Al 2 O 3 atomic layer deposition, the number of ALD cycles ≥ 30 times.

[0022] For the gradient heat-dissipating composite transfer roller of the present invention, the ALD process parameters include:

[0023] Al2 O 3 Deposition: Trimethylaluminum pulse for 0.1 s, purge for 20 s;

[0024] TiO 2 Deposition: Titanium tetrachloride pulse for 0.2 s, purge for 25 s;

[0025] The total thickness of the composite coating is ≤ 7 nm, and the dielectric constant ε = 9 - 11.

[0026] For the gradient heat-dissipating composite transfer roller of the present invention, a heat-conducting medium is provided in the microchannel.

[0027] For the gradient heat-dissipating composite transfer roller of the present invention, the preparation steps of the composite rubber tube layer further include the following steps after the cutting and vulcanization:

[0028] Grooving and bonding: Axial grooves are formed on the surface of the metal shaft core, and carbon fiber reinforcement strips are embedded in the grooves. The reinforcement strips are connected to the matrix layer through sulfur bonding. The depth of the grooves is 1 mm and the width is 2 mm.

[0029] For the gradient heat-dissipating composite transfer roller of the present invention, the preparation steps of the composite rubber tube layer further include the following steps after the grooving and bonding:

[0030] Insertion and grinding: The composite rubber tube layer is sleeved on the metal shaft core and ground to a grinding wheel mesh number of 36, and the grinding speed is 1500 r / min.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: Through the design of a radial four-layer gradient structure, that is, including a matrix layer, a void layer, a transition layer and a surface layer, combined with a double-helix conductive network and a microchannel heat dissipation system, and coordinated with gradient co-extrusion and a specific vulcanization process, a breakthrough improvement in resistance stability and heat dissipation efficiency is achieved, so that the resistance change of the transfer roller can be less than 3.2% / 1000 h, and a good stable conductivity can still be maintained when the peak temperature exceeds 138 °C. The improved transfer roller is particularly suitable for high-speed printing equipment, and its service life can reach several times that of traditional products. Description of the Drawings

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for the description of the specific embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0033] Figure 1 It is a structural schematic diagram of the present invention. Detailed Embodiments

[0034] In the description and claims of the present invention and the terms "first", "second", "third", "fourth", etc. in the accompanying drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0035] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0036] "A plurality of" means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally represents an "or" relationship between the associated objects before and after.

[0037] Moreover, the terms indicating directions such as "upper", "lower", "left", "right", "upper end", "lower end", "longitudinal", etc. are all referenced based on the attitude position of the device or equipment described in this solution during normal use.

[0038] In order to make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are partial embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present invention.

[0039] This embodiment discloses a gradient dispersion composite transfer roller as shown in Figure 1 which includes a metal shaft core 10 and a composite rubber tube layer 20 coated on its outer sidewall, characterized in that the composite rubber tube layer 20 sequentially includes a base layer 21, a void layer 22, a transition layer 23, and a surface layer 24 from the inside to the outside in the radial direction; microchannels are provided radially inside the void layer;

[0040] The composite rubber tube layer is prepared by the following steps:

[0041] Ingredients: Weigh 100 parts of nitrile rubber, 20 parts of chlorinated polyether rubber, 6 parts of ionic conductive agent, 70 - 90 parts of filler, 3 - 6 parts of accelerator, and 5 - 7.5 parts of foaming agent by weight, and seal for later use; among them, the ionic conductive agent is a quaternary ammonium salt ionic liquid with the molecular formula [C 4 mim][TFSI], with a conductivity ≥ 10 -3 S / cm, which can increase the carrier concentration several times (Hall effect test), and the decomposition temperature > 300 °C to avoid the failure of the conductive agent at high temperatures; while the filler is precipitated silica (specific surface area ≥ 150 m 2 / g), the accelerator is tetramethylthiuram disulfide (TMTD), the foaming agent is azodicarbonamide (AC), and the silica (specific surface area ≥ 150 m 2 / g) increases the tensile strength of the rubber layer from 8 MPa to 12 MPa (ASTM D638). The decomposition product of the AC foaming agent is N 2 / CO 2 , and the VOC emission is greatly reduced (detected by GC - MS);

[0042] Rubber mixing: Mix the nitrile rubber and chlorinated polyether rubber until 80 °C ± 5 °C and keep it for 5 - 8 minutes. After adding the conductive agent and filler, heat it up to 130 °C ± 5 °C and mix for 20 - 30 minutes;

[0043] Extrusion foaming: After cooling the mixed rubber for 24 hours, perform extrusion foaming with an extrusion flow rate of 4.5 - 6 and a foaming speed of 4. The temperature gradient is 180 °C - 220 °C. Specifically, the screw rotation speed of 30 - 40 rpm ensures the uniform dispersion of the foaming agent, and the foaming pore diameter is distributed between 50 - 200 μm (measured by SEM). The standard deviation of the pore diameter distribution decreases from ±45 μm to ±15 μm. Among them, the actual temperature is controlled between 160 °C - 180 °C, so that the decomposition temperature window of the foaming agent matches the vulcanization curve of the nitrile rubber, further reducing the deviation of the foaming rate;

[0044] Gradient co - extrusion: Simultaneously form the matrix layer, void layer, transition layer, and surface layer. The temperature of the co - extrusion die head is distributed in a layer - wise gradient as 180 °C → 220 °C;

[0045] Cutting and vulcanization: Cut the foamed tube to the length of the transfer roller and vulcanize it at 150 °C for 1 hour.

[0046] Through the design of a radial four-layer gradient structure, that is, including a matrix layer, a void layer, a transition layer, and a surface layer, combined with a double-helix conductive network and a microchannel heat dissipation system, and through collaborative gradient co-extrusion and a specific vulcanization process, a breakthrough improvement in resistance stability and heat dissipation efficiency is achieved. The resistance change of the transfer roller is less than three percentage points per 1000 h, and a good stable conductivity can still be maintained when the peak temperature exceeds 138 °C. The improved transfer roller is particularly suitable for high-speed printing equipment, and its service life can reach several times that of traditional products.

[0047] In this embodiment, the matrix layer is a nitrile rubber layer containing silver-plated glass fibers, with a thickness of 4.5 ± 0.2 mm and a volume resistivity ≤ 10 2 Ω·cm;

[0048] The void layer has a porosity of 40 ± 2% and radially embedded microchannels inside;

[0049] The transition layer is a nitrile rubber layer containing Al 2 O 3 fibers and coated with carbon nanotubes, with a thickness of 1.0 ± 0.1 mm and an axial thermal conductivity ≥ 12 W / mK;

[0050] The surface layer is a nitrile rubber layer containing vertically oriented carbon nanotubes and boron nitride nanosheets, with a thickness of 0.5 ± 0.05 mm and a surface resistivity ≤ 10E+07 Ω·cm.

[0051] Furthermore, axially helically wound carbon fiber filaments can be embedded in the void layer, so that the carbon fiber filaments and Al 2 O 3 fibers form a double-helix conductive network, and the two helical structures are cross-designed, which can provide a low-resistance path in the axial main helix to achieve micro-region current shunting and reduce the resistance volatility; and the cross-winding angle disperses the strain of the conductive network under axial tension to improve the elongation at break.

[0052] In this embodiment, the microchannels are prepared by the following process:

[0053] Use a 355 nm ultraviolet laser to engrave the void layer radially from the inside to the outside, and the engraving parameters are a pulse energy of 50 μJ and a scanning speed of 2 m / s.

[0054] In this embodiment, the rubber mixing step specifically includes: mixing nitrile rubber and chloromethyl ether rubber to 80 °C ± 5 °C, lasting for 5 - 8 minutes, and adding conductive agents and fillers under a 1.5 T vertical magnetic field and then heating to 130 °C ± 5 °C, mixing for 20 - 30 minutes, and synchronously applying a 10 kHz ultrasonic vibration.

[0055] In this embodiment, the cutting and vulcanization step specifically includes:

[0056] Cut the foaming tube to the length of the transfer roller, vulcanize it in a 2.45 GHz microwave field at 150 °C for 1 hour, and simultaneously perform Al 2 O 3 atomic layer deposition. Further, after the vulcanization process, limit the crosslinking density and resistivity of the composite rubber tube layer to ensure that the crosslinking density ≥ 85% (measured by the swelling method), the volume resistivity volatility ≤ 5% (1000-hour aging test), and the swelling degree (toluene immersion for 24 h) decreases from 120% to 35%, which can greatly avoid large deformations during use.

[0057] In this embodiment, Al 2 O 3 The number of ALD cycles in atomic layer deposition ≥ 30 times.

[0058] In this embodiment, the ALD process parameters include:

[0059] Al 2 O 3 Deposition: Trimethylaluminum pulse for 0.1 s, purge for 20 s;

[0060] TiO 2 Deposition: Titanium tetrachloride pulse for 0.2 s, purge for 25 s;

[0061] The total thickness of the composite coating ≤ 7 nm, and the dielectric constant ε is between 9 and 11.

[0062] In this embodiment, a heat-conducting medium is filled in the microchannel to match the heat dissipation requirements under different loads (temperature difference < 5 °C), and a periodic bending structure can also be set in the microchannel to induce local eddies to enhance the turbulent heat transfer effect.

[0063] In this embodiment, the preparation steps of the composite rubber tube layer further include the following steps after cutting and vulcanization:

[0064] Grooving and bonding: Axial grooves 30 are opened on the surface of the metal shaft core, and carbon fiber reinforcing strips are embedded in the grooves 30. The reinforcing strips are bonded to the matrix layer through sulfur bonds. Among them, the depth of the groove is 1 mm and the width is 2 mm; the axial modulus of the carbon fiber reinforcing strips (230 GPa) improves the torsional strength of the transfer roller and maintains good non-deformation ability in the torque test; and the sulfur bond can also further improve the adhesive strength between the rubber layer and the shaft core;

[0065] In this embodiment, the preparation steps of the composite rubber tube layer further include the following steps after grooving and bonding:

[0066] Embedded grinding: The composite rubber hose layer is sleeved on the metal core and ground to a grinding wheel mesh number of 36. The grinding speed is 1500 r / min. After the grinding process, the surface roughness Ra of the transfer roller is ≤ 1.6 μm, which slightly improves the toner transfer efficiency (tested at 1200 dpi), and ensures that the radial runout tolerance is further reduced, so that the vibration amplitude of the transfer roller at high speed rotation (1500 r / min) is reduced.

[0067] It should be understood that those of ordinary skill in the art can make improvements or transformations according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A gradient diffusion composite transfer roller, comprising a metal shaft core and a composite rubber hose layer coated on its outer side wall, characterized in that: The composite rubber hose layer includes a base layer, a void layer, a transition layer and a surface layer in order from the inside to the outside in radial direction; a microchannel is radially arranged in the void layer; The composite hose layer is prepared by the following steps: Ingredients: weigh 100 parts of nitrile rubber, 20 parts of chloroether rubber, 6 parts of ion conductive agent, 70-90 parts of filler, 3-6 parts of accelerator, 5-7.5 parts of foaming agent by weight, seal and set aside; Rubber mixing: Mix nitrile rubber and chloroether rubber to 80℃±5℃ for 5-8 minutes, add conductive agent and filler, raise the temperature to 130℃±5℃, and mix for 20-30 minutes; Extrusion foaming: After cooling the rubber compound for 24 hours, extrusion foaming was performed at an extrusion flow rate of 4.5-6 and a foaming speed of 4, with a temperature gradient of 180°C-220°C; Gradient co-extrusion: The base layer, interstitial layer, transition layer and surface layer are formed simultaneously. The temperature of the co-extrusion die head is distributed in a gradient of 180℃→220℃ according to the layer position. Cutting and vulcanization: Cut the foam tube into the length of the transfer roller and vulcanize it at 150℃ for 1 hour.

2. The gradient dispersion composite transfer roller according to claim 1, characterized in that: The base layer contains a nitrile rubber layer of silver-coated glass fiber, with a thickness of 4.5±0.2mm and a volume resistivity of ≤10 2 Ω·cm; The void layer has a porosity of 40±2% and is internally embedded with radial microchannels; The transition layer is a nitrile rubber layer containing Al2O3 fibers and coated with carbon nanotubes, with a thickness of 1.0±0.1mm and an axial thermal conductivity of ≥12W / mK; The surface layer comprises a nitrile rubber layer of vertically oriented carbon nanotubes and boron nitride nanosheets, with a thickness of 0.5±0.05 mm and a surface resistivity of ≤10E+0.7Ω·cm.

3. The gradient dispersion composite transfer roller according to claim 2, characterized in that: The microchannel is prepared by the following process: The gap layer is radially engraved from the inside to the outside using a 355 nm ultraviolet laser, and the engraving parameters are a pulse energy of 50 μJ and a scanning speed of 2 m / s.

4. The gradient dispersion composite transfer roller according to claim 1, characterized in that: The rubber refining step specifically includes: mixing nitrile rubber and chloroether rubber to 80°C±5°C for 5-8 minutes, adding a conductive agent and a filler under a 1.5T vertical magnetic field, heating to 130°C±5°C, mixing for 20-30 minutes, and simultaneously applying 10kHz ultrasonic vibration.

5. The gradient dispersion composite transfer roller according to claim 1, characterized in that: The cutting and vulcanization step specifically comprises: The foamed tube was cut into the length of the transfer roller, and was sulfurized at 150°C and in a 2.45 GHz microwave field for 1 hour, and Al2O3 atomic layer deposition was performed simultaneously.

6. The gradient dispersion composite transfer roller according to claim 5, characterized in that: The number of ALD cycles in simultaneous Al2O3 atomic layer deposition is ≥30 times.

7. The gradient dispersion composite transfer roller according to claim 6, characterized in that: The ALD process parameters include: Al2O3 deposition: trimethylaluminum pulse 0.1s, purge 20s; TiO2 deposition: titanium tetrachloride pulse 0.2s, purge 25s; The total thickness of the composite coating is ≤7nm, and the dielectric constant ε is 9-11.

8. The gradient dispersion composite transfer roller according to claim 1, characterized in that: A heat-conducting medium is arranged in the microchannel.

9. The gradient dispersion composite transfer roller according to any one of claims 1 to 8, characterized in that: The preparation step of the composite hose layer also includes the following steps after the cutting and vulcanization: Slotted bonding: An axial groove is provided on the surface of the metal shaft core, a carbon fiber reinforcement strip is embedded in the groove, and the reinforcement strip is connected to the base layer through sulfur bonding, wherein the groove has a depth of 1 mm and a width of 2 mm.

10. The gradient dispersion composite transfer roller according to claim 9, characterized in that: After the slotting and bonding steps, the preparation steps of the composite hose layer further include: Embedded grinding: The composite hose layer is sleeved on the metal shaft core and ground to a grinding wheel mesh number of 36, wherein the grinding speed is 1500r / min.

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