WO2013117127A1

WO2013117127A1 - Method for manufacturing scraping knife

Info

Publication number: WO2013117127A1
Application number: PCT/CN2013/070812
Authority: WO
Inventors: 宋道权
Original assignee: 珠海天威飞马打印耗材有限公司
Priority date: 2012-02-08
Filing date: 2013-01-22
Publication date: 2013-08-15
Also published as: CN102529013A

Abstract

The present invention provides a method for manufacturing a scraping knife by using a double-material injection molding machine. The scraping knife comprises a knife rest made of ebonite and a blade made of soft rubber. Steps for manufacturing the scraping knife comprises: preparing a die; adding materials; performing injection molding of the knife rest; performing injection molding of the blade; and de-molding.

Description

Scraper manufacturing method

The present invention relates to a component of an electrophotographic image forming apparatus, and more particularly to a method of making a doctor blade in a process cartridge of an electrophotographic apparatus. The present invention is based on a Chinese invention patent application filed on Feb. 08, 2012, the application number of which is incorporated herein by reference.

An electrophotographic image forming apparatus is an apparatus for forming an image on a recording material by electrophotographic image forming processing, and includes an electrophotographic copying machine, an electrophotographic printer, an electrophotographic printing facsimile machine, and the like. A process cartridge used in an electrophotographic image forming apparatus using the principle of electrophotographic imaging is a unit cartridge including at least a developing roller as a developing device and an electrophotographic photosensitive drum, and the process cartridge is detachably mountable to a main body of the electrophotographic image forming apparatus on.

A typical electrophotographic imaging device is a laser printer. Laser printer is one of the most widely used external computer output devices. It uses the physical, chemical, and chemical principles of light, electricity, and heat to output text or images through interaction. The basic working process of a laser printer can be divided into seven steps: charging, exposure, development, transfer, fixing, cleaning, and power-saving. First, the surface of the photosensitive drum is uniformly charged by a charging roller, and the laser scanner emits a modulated laser light containing image information to the photosensitive drum to form an electrostatic latent image corresponding to the image to be reproduced on the surface of the photosensitive drum. Then, the toner from the developing roller is adsorbed on the surface of the photosensitive drum to convert the electrostatic latent image into a visible image, and the visible image formed on the surface of the photosensitive drum is transposed to the transfer roller as the photosensitive drum rotates. . Finally, under the action of the transfer voltage of the transfer roller, the visible image is transferred onto a recording medium such as paper, and the visible image on the recording medium is heated and pressurized by the heating roller and the pressure roller, and the carbon powder is formed. The visible image is completely cured on the recording medium, which is the basic imaging process of the laser printer. The basic imaging process is repeated as the laser printer is used.

The developing roller adsorbs the toner in the toner hopper on the surface thereof by electrostatic adsorption. Before the toner on the developing roller is transferred to the photosensitive drum, the toner on the surface of the developing roller needs to be flattened to a suitable thickness by a powder discharging blade to ensure uniformity of development. The blade of the powder discharging blade elastically contacts the circumferential surface of the developing roller along the axial direction of the developing roller, and the length of the discharging blade is the same as the axial length of the developing roller. It is the key to excellent print quality to have a uniform and appropriate thickness of the toner layer on the surface of the developing roller by the powder scraping blade.

Before the drum is reused, its last working process leaves a residual potential on the surface of the drum, and a small amount of toner remains on the surface of the drum due to the attraction of the residual potential to the toner. Transfer efficiency can be improved only by eliminating residual potential and residual toner. Therefore, it is necessary to clean and discharge the photosensitive drum. The pre-exposure is usually used for the elimination of electricity, and the cleaning blade is usually used for cleaning. The cleaning blade is closely attached to the circumferential surface of the photosensitive drum along the axial direction of the photosensitive drum, and the length of the cleaning blade is the same as the axial length of the photosensitive drum. During the rotation of the photosensitive drum, the cleaning blade scrapes off the residual toner on the surface, carbon The powder falls into the waste toner box.

Both the powder scraper and the cleaning blade are composed of a tool holder and a blade fixed to the tool holder, the difference being that the width of the powder blade holder is narrower than the width of the cleaning blade holder. The powder scraper and the cleaning scraper are collectively referred to as a scraper.

Existing scrapers are available in two configurations: strip and all metal. The strip type scraper is composed of a strip as a blade and a metal holder, and the support end extending along the length of the strip is fixed to the metal holder by an adhesive. The all-metal type scraper is composed of a metal blade and a metal tool holder, and the support end edge of the metal blade extending along the length direction is fixed to the metal tool holder by welding.

The manufacturing process of the existing scraper: the manufacturing process of the strip type scraper is to first make a metal knife holder through a stamping forming process, make a strip by an extrusion molding process, and finally bond the strip to the metal knife holder; the full metal type The manufacturing process of the scraper is to first make a metal tool holder and a metal blade by a stamping process, and finally fix the metal tool holder and the metal blade by welding.

Since metal is more expensive than plastic, most scrapers use strips as blades to save costs. In the production process of the strip type scraper, the adhesive used to bond the strip to the metal knife holder is a toxic glue with a pungent odor, and long-term contact with the glue may cause harm to the human body. In addition, the existing scraper has many production processes, and the flatness of the scraper and the blade are easily reduced during assembly, which affects the quality of the scraper.

It is an object of the present invention to provide a method of manufacturing a doctor blade which has few production processes, is both cost-effective and environmentally friendly.

In order to achieve the above object, the scraping knife provided by the present invention comprises a knife holder made of a hard rubber material and a blade made of a soft rubber material, and the manufacturing steps thereof include:

Mold: a mold for making a doctor blade, the mold includes a blade cavity and a die cavity, and the blade cavity is filled by a movable core;

Adding material: adding a hard rubber material to the hopper of the main injection device of the double material injection molding machine, and adding a soft rubber material to the hopper of the auxiliary rubber injection device of the double material injection molding machine;

Injection mold holder: The main injection device plasticizes and melts the hard rubber material, injects the melt into the mold cavity of the tool holder, and after the mold cavity is filled and held, the mold core is withdrawn from the blade mold cavity;

Injection molding blade: The secondary injection device plasticizes and melts the soft rubber material, fills the melt into the blade cavity, fills the blade cavity and holds the pressure;

Demoulding: After the mold cavity and the blade cavity are cooled and shaped, the blade is ejected.

A specific solution is that the hard rubber is glass fiber reinforced polyphenylene sulfide (PPS + GF), glass fiber reinforced polycarbonate (PC + GF) or polybutylene terephthalate (PBT). The tool holder of the scraper made of the preferred material in this solution has the characteristics of stable structure, non-deformation and good elasticity.

Another specific solution is that the soft rubber is a thermoplastic polyurethane elastomer (TPU) or a polyamide resin (PA). The blade of the blade made of the preferred material in this solution has good wear resistance and a certain strength.

Yet another specific solution is that the mold is a die of a doctor blade that includes a cavity of a blade and a cavity of a tool holder. One scraper can be formed at a time, and the production process is simple and easy to operate.

A further solution of the above solution is that in the step of the injection mold holder, the nozzle temperature of the main injection device is 255 to 285 ° C, and the temperature of the heating barrel of the main injection device is divided from the feed end to the discharge end. The interval is 245-265 ° C, 270-290 ° C, 275-295 ° C and 275-295 ° C; in the injection molding step, the nozzle temperature of the auxiliary injection device is 170-180 ° C, and the heating barrel of the auxiliary injection device The four temperature zones from the feed end to the discharge end are 170-180 ° C, 180-190 ° C, 185-195 ° C and 185-195 ° C, respectively. According to the characteristics of the scraper hard rubber and soft rubber material, this temperature range can be used to obtain a scraper with good plasticity and strength.

Another further solution is that in the injection mold step, the screw speed is 149.5r/min, the injection pressure is 181.8Mpa, the injection time is 4.2s, the holding pressure is 97.0Mpa, the dwell time is 3.0s, and the cooling time is 18.0. s; in the injection molding step, the screw speed is 126.5r/min, the injection pressure is 131.3Mpa, the injection time is 4.5s, the holding pressure is 121.2Mpa, the dwell time is 3.0s, and the cooling time is 16.0s; After the injection mold holder step is completed, the mold cavity is cooled by 2.0 s and the injection molding step is started. After the injection molding step is completed, the mold cavity and the blade cavity are cooled together for 16.0 s. According to the shape characteristics of the scraper structure applicable to the processing box, the relevant parameters in the scheme are selected to ensure that the knife holder and the blade of the scraper have good injection molding effect, and the scraper has a stable structure.

A further specific solution is that the mold is a mold of two connected doctor blades, comprising two connected blade cavities and one tool holder cavity on each side of the two adjacent blade cavities; and adding cutting after the demolding step Step: The cutting edge of the cutting machine is aligned with the center line extending along the long axis direction of the two connected scraping blades, and the two connecting scraping blades are divided into two, that is, two independent scraping blades are obtained.

A specific solution is that in the step of the injection mold holder, the nozzle temperature of the main injection device is 255 to 285 ° C, and the four temperature intervals of the heating barrel of the main injection device are divided from the feeding end to the discharge end. The order is 245 ~ 265 ° C, 270 ~ 290 ° C, 275 ~ 295 ° C and 275 ~ 295 ° C; in the injection molding step, the nozzle temperature of the sub-ejection device is 170 ~ 180 ° C, the heating barrel of the sub-adhesive device The four temperature zones of the feed end to the discharge end are 170-180 ° C, 180-190 ° C, 185-195 ° C and 185-195 ° C, respectively. According to the characteristics of the scraper hard rubber and soft rubber material, this temperature range can be used to obtain a scraper with good plasticity and strength.

Another specific solution is that in the injection tool holder step, the screw speed is 149.5r/min, the injection pressure is 181.8Mpa, the injection time is 5s, the holding pressure is 112.5Mpa, the dwell time is 3.5s, and the cooling time is 22s. In the injection molding step, the screw speed is 138r/min, the injection pressure is 141.4Mpa, the injection time is 4.5s, the holding pressure is 112.5Mpa, the holding time is 3s, and the cooling time is 20s; After completion, the tool holder cavity is cooled for 2 seconds and the injection molding step is started. After the injection molding blade step is completed, the tool holder cavity and the two connected blade cavities are cooled together for 20 s. According to the shape characteristics of the scraper structure applicable to the processing box, the relevant parameters in the scheme are selected to ensure that the knife holder and the blade of the scraper have good injection molding effect, and the scraper has a stable structure.

The invention reduces the cost of producing raw materials, adopts the double material injection molding machine to form the scraper in one time, reduces the process, improves the production efficiency, and no longer uses the toxic glue in the process of making the scraper, and the production process is safe and environmentally friendly.

In addition, two scrapers are produced at one time through the injection molding process, which reduces production processes, improves production efficiency, and is safe and environmentally friendly in the production process.

Figure 1 is a structural view showing two connected doctor blades produced by the first embodiment of the doctor blade manufacturing method of the present invention;

Figure 2 is a structural view of a doctor blade produced by the first embodiment of the blade making method of the present invention;

Figure 3 is a partial enlarged view of A in Figure 2;

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The apparatus used in the method for making the doctor blade of the present invention is a two-material injection molding machine. The known two-material injection molding machine is used for manufacturing a workpiece composed of two materials, and the workpiece is formed in one production cycle. The two-material injection molding machine has two sets of primary and secondary injection devices. The primary and secondary injection devices are arranged at an angle of 90 degrees. The primary injection device injects one material into the main cavity, and the secondary injection device is another. The material is injected into the auxiliary cavity, and the main injection device and the secondary injection device simultaneously complete the injection molding.

The double material injection molding machine has a clamping device on the body, and the clamping device functions to fix the mold, wherein the movable template is used for opening and closing the mold movement, and the mold can be locked.

The primary and secondary injection devices have the same structure, and only the structure of the primary injection device will be described herein, and the description of the secondary injection device will be omitted. The main injection device has a rubber injection seat, and the injection rubber seat can be moved relative to the body of the double material injection molding machine. The plasticizing part, the injection part and the hopper of the main injection device are fixed on the injection seat. The plasticizing department mainly includes a screw, a heating barrel, and the like, and the injection part mainly includes an injection cylinder, a piston, and a nozzle. The feeding end of the heating barrel is for receiving material from the hopper, the discharging end of the heating barrel is in communication with the nozzle, and the nozzle is in communication with the flow path of the mold. The heating barrel is provided with a screw and a heating ring, and the material can be quickly plasticized and melted under the heating of the screw and the heating coil of the barrel, and the molten melt is injected from the nozzle under the injection thrust of the injection cylinder. Cavity cavity.

First embodiment

Scraper making method steps

Spare mode

The mold of the mold clamping device is designed in accordance with the structure of the two connected doctor blades shown in FIG. The two doctor blades shown in Fig. 1 have the same structure, the blade edges 3 of the blades 2 of the two doctor blades are aligned and joined together, and the connected blades 2 are located in the same plane, and the support end of each blade holder 1 is the same toward the blade 2 Side bending. The mold of the mold and the core of the fixed mold enclose two adjacent blade cavities and two tool holder cavities, wherein the fixed mold has a movable core filling the two adjacent blade cavities.

Feeding

Add hard rubber to the hopper of the main injection equipment of the double material injection molding machine. The hard rubber can be selected from glass fiber reinforced polyphenylene sulfide (PPS+GF), glass fiber reinforced polycarbonate (PC+GF) or polyparaphenylene. Any of the butylene dicarboxylate (PBT). At the same time, the soft rubber is added to the hopper of the auxiliary rubber injection device of the double material injection molding machine, and the soft rubber material may be a thermoplastic polyurethane elastomer (TPU) or a polyamide resin (PA).

Set injection parameters and inject two connected scrapers

The entire injection molding process of the two-material injection molding machine is controlled by the CPU to control the operation of the clamping mechanism, the main and secondary injection molding devices, and the related power mechanisms such as the injection cylinder.

The input control window of the injection molding parameters on the CPU control panel of the two-material injection molding machine includes five plasticizing temperatures, screw speed, injection pressure, holding pressure, injection time and cooling time.

Wherein, the five plasticizing temperatures are respectively a temperature range of the four sections of the heating barrel inner cavity along the axial length and the temperature range of the nozzle, and the temperature in the heating barrel near the feeding end is lower, close to the nozzle end The temperature is higher. The screw is driven by a screw motor, and the screw speed can affect the melting speed of the material. Injection pressure refers to the pressure exerted by the screw or plunger head on the plastic melt during the injection molding process. The holding pressure is the pressure in the cavity, the injection time is the time when the material is injected into the cavity, the holding time is the time to maintain the constant pressure in the cavity, and the cooling time is the time of cooling and setting. These parameter values are usually obtained by modifying the structure and material of the blade and after several tests.

The parameter setting values of this embodiment are shown in Table 1 given in FIG.

The CPU executes the injection molding process according to the set parameter values:

First injection of two tool holders: the two insert cavities are filled by the core, and the hard rubber enters the heating barrel. Under the high temperature and the rotation of the screw, the hard rubber is plasticized, melted into a melt, and the melt passes through the nozzle. Injecting a flow path communicating with the two tool holder cavities until filling the two tool holder cavities;

Re-injecting two connected blades: After the two tool holder cavities are cooled for 2 s, the movable core retracts and exits the two connected blade cavities, and the soft rubber enters the heating cylinder, and under the high temperature and the rotation of the screw, The soft compound is plasticized and melted into a melt, and the melt is injected into the flow path communicating with the two connected blade cavities through the nozzle until it is filled with two connected blade cavities;

Cooling and demoulding: After cooling the two connected scrapers in the mold for 20 s, the mold is opened and the two connected scrapers are ejected from the cavity.

Made a separate scraper

Cutting: The two connected scrapers are divided into two by a cutting machine, and the cutting edge of the cutting machine is aligned with the center line extending along the long axis direction of the two connected scraping blades to obtain two independent scraping blades.

Referring to Fig. 2, the doctor blade shown in Fig. 2 is one of the doctor blades obtained by cutting the two adjacent doctor blades shown in Fig. 1. As can be seen from the partial enlarged view of FIG. 2, FIG. 3, the scraper can be used to form a scraper blade that is firmly connected between the blade 2 and the tool post 1 by an injection molding process. Specifically, the tool post 1 is provided with a convex portion at one end of the mounting blade 2. 101, the projection 101 projects into the blade 2, which makes the connection between the blade holder 1 and the blade 2 stronger.

Second embodiment

Scraper making method steps

Spare mode

A mold for making a doctor blade, comprising a blade cavity and a die cavity, the blade cavity and the die cavity are surrounded by a mold of the mold and a core on the fixed mold, wherein the fixed mold has a movable body The core fills the blade cavity.

Feeding

Set injection parameters and mold a scraper

The parameter setting values of the two-material injection molding machine are shown in Table 2 given in Figure 2.

The CPU of the two-material injection molding machine performs the injection molding process according to the set parameter values:

First injection molding: the blade cavity is filled by the core, and the hard rubber enters the heating cylinder. Under the high temperature and the rotation of the screw, the hard rubber is plasticized and melted into a melt, and the melt is injected into the tool holder through the nozzle. The flow path connecting the cavity until the mold cavity is filled, and then the pressure is maintained;

Re-injection insert: After the mold cavity is cooled for 2s, the movable core retracts from the insert cavity, and the soft rubber enters the heating cylinder. The soft rubber is plasticized and melted under the high temperature and the rotation of the screw. Melting, the melt is injected into the flow path communicating with the blade cavity through the nozzle until the blade cavity is filled, and then the pressure is maintained;

Cooling and demoulding: After cooling the scraper in the mold for 16s, the mold is opened and the scraper is ejected from the cavity to produce a scraper. The structure of the scraper can be seen in Figure 2.

The scraper provided by the invention is made of all plastic materials, and the two connected scrapers prepared by the injection molding process only need to be cut by the cutter to complete the scraper, and the flatness of the scraper surface can be well maintained in the production process, and the flatness of the scraper is good. Improve the quality of powder control.

Claims

A doctor blade manufacturing method comprising a knife holder made of a hard rubber material and a blade made of a soft rubber material, characterized in that:

The manufacturing steps of the scraper include

Overmolding: a mold for making a doctor blade, the mold comprising a blade cavity and a tool holder cavity, and the blade cavity is filled by a movable core;

Adding material: adding a hard rubber material to the hopper of the main injection device of the double material injection molding machine, and adding a soft rubber material to the hopper of the auxiliary rubber injection device of the double material injection molding machine;

Injection molding tool holder: injecting into the mold cavity of the tool holder by the main injection device, and after the mold cavity of the tool holder is filled and held, the core is withdrawn from the blade cavity;

Injection molding blade: the auxiliary injection device is injected into the blade cavity, and the blade cavity is filled and held;

Demolding: After the mold cavity and the blade cavity are cooled and shaped, the blade is ejected.
The scraper manufacturing method according to claim 1, wherein:

The hard rubber is glass fiber reinforced polyphenylene sulfide (PPS+GF), glass fiber reinforced polycarbonate (PC+GF) or polybutylene terephthalate (PBT).
The scraper manufacturing method according to claim 1, wherein:

The soft rubber is a thermoplastic polyurethane elastomer (TPU) or a polyamide resin (PA).
The scraper manufacturing method according to claim 1, wherein:

The mold is a die of a doctor blade that includes a cavity of a blade and a cavity of a tool holder.
The scraper manufacturing method according to claim 4, wherein:

In the step of the injection molding tool holder, the nozzle temperature of the main injection device is 255 to 285 ° C, and four temperature intervals of the heating barrel of the main injection device are divided from the feeding end to the discharging end. 245 to 265 ° C, 270 to 290 ° C, 275 to 295 ° C and 275 to 295 ° C;

In the step of the injection molding blade, the nozzle temperature of the sub-adhesive device is 170-180 ° C, and the four temperature zones of the heating barrel of the sub-adhesive device from the feeding end to the discharging end are in turn 170 to 180 ° C, 180 to 190 ° C, 185 to 195 ° C and 185 to 195 ° C.
A method of manufacturing a doctor blade according to claim 4 or 5, wherein:

In the step of the injection mold holder, the screw rotation speed is 149.5r/min, the injection pressure is 181.8Mpa, the injection time is 4.2s, the pressure holding pressure is 97.0Mpa, the pressure holding time is 3.0s, and the cooling time is 18.0s;

In the injection molding step, the screw rotation speed is 126.5r/min, the injection pressure is 131.3Mpa, the injection time is 4.5s, the holding pressure is 121.2Mpa, the dwell time is 3.0s, and the cooling time is 16.0s;

After the step of injecting the tool holder is completed, the mold cavity of the tool holder is cooled for 2.0 seconds and then the injection molding blade step is started. After the injection molding blade step is completed, the tool holder cavity and the blade are finished. The mold cavity was cooled together for 16.0 s.
The scraper manufacturing method according to claim 1, wherein:

The mold is a mold of two connected doctor blades, comprising two connected blade mold cavities and one tool holder cavity on each side of the two connected blade mold cavities;

And adding a cutting step after the demolding step: the cutting edge of the cutting machine is aligned with the center line extending along the long axis direction of the two connected scraping blades, and the two connecting scraping blades are divided into two, that is, two independent scraping blades are obtained .
The scraper manufacturing method according to claim 7, wherein:

In the step of the injection molding tool holder, the nozzle temperature of the main injection device is 255 to 285 ° C, and four temperature intervals of the heating barrel of the main injection device are divided from the feeding end to the discharging end. 245 to 265 ° C, 270 to 290 ° C, 275 to 295 ° C and 275 to 295 ° C;

In the step of the injection molding blade, the nozzle temperature of the sub-adhesive device is 170-180 ° C, and the four temperature zones of the heating barrel of the sub-adhesive device from the feeding end to the discharging end are in turn 170 to 180 ° C, 180 to 190 ° C, 185 to 195 ° C and 185 to 195 ° C.
The scraper manufacturing method according to claim 7 or 8, wherein:

In the step of the injection mold holder, the screw rotation speed is 149.5r/min, the injection pressure is 181.8Mpa, the injection time is 5s, the pressure is 112.5Mpa, the pressure holding time is 3.5s, and the cooling time is 22s;

In the injection molding step, the screw rotation speed is 138r/min, the injection pressure is 141.4Mpa, the injection time is 4.5s, the holding pressure is 112.5Mpa, the dwell time is 3s, and the cooling time is 20s;

After the step of injecting the tool holder is completed, the tool holder cavity is cooled for 2 seconds and then the injection molding blade step is started. After the injection molding blade step is completed, the tool holder cavity and the two are The connected blade cavities are cooled together for 20 s.