Recycling and maintenance of laser printer drum components
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The laser printer is an integrated, highly automated computer output device developed in 1980 that integrates optical technology, electronic technology and mechanical technology. Although there are many types of laser printers, both black and white or color are composed of a laser scanning system and a toner cartridge and a circuit portion mainly composed of toner and photosensitive drum.
First, the working principle
The working principle of most laser printers can be divided into six steps:
1. Drum charging process
At the start of printing, the photosensitive drum is uniformly charged with a negative charge on the outer surface of the drum. The primary corona discharge electrode is installed in a long and narrow slot, and a high voltage power supply is used to apply a high voltage to the primary corona discharge electrode, so that the corona discharge electrode has a high voltage of 6000V, and the high pressure makes the surrounding air movable. Electric ion. Below the primary corona discharge electrode is a gate. The gate usually has a voltage of -600V, which can attract the electric ions in the air around the corona discharge electrode, and the negatively charged ions move toward the surface of the photosensitive drum. When moving, it again limits the voltage of the negative ions, so that a uniform layer of -600V is placed on the surface of the photosensitive drum.
2. Exposure process
After the charging process is completed, the laser generator generates a laser beam, which is reflected by the scanning mirror onto the photosensitive drum, so that the photosensitive layer of the irradiated portion (character or image) becomes a conductor, and the -600 V charge on the surface thereof is directed to the ground. The bleed, which becomes a low voltage of about -100V, at this time, an image point with a voltage of -100V is written on the surface of the photosensitive drum, that is, an electrostatic latent image point of an invisible text or image, and thus, The exposed drum surface still retains a charge of -600V.
3. Developing (onner) process
The development is mainly to toner on the photosensitive electrostatic latent image on the photosensitive drum to obtain visible text or image dots. During the rotation of the photosensitive drum, after the latent image point meets the toner on the developing roller (drum), the high-voltage electric toner is adsorbed by the latent image point on the lower-voltage photosensitive drum, at this time on the photosensitive drum The -100V latent image becomes a visual text or image.
4. Transfer process
When the developed photosensitive drum continues to rotate, when the photosensitive drum surface passes through the transfer corona pole, the developed text or image toner is transferred onto the printing paper. Because the positive charge on the back side of the paper strongly adheres the text or image dots of the negatively charged toner on the drum to the paper. At the same time, a negative charge is also generated on the static eliminator to eliminate the attraction between the photosensitive drum and the printing paper, so that the printing paper can be easily separated from the photosensitive drum without being attracted.
5. Fixing process
When the text or image is transferred to the paper, it is further cured by the fuser (warming). When the printing paper passes through the fuser, the high temperature in the fuser is melted at 180 ° C - 220 ° C, and the pressure between the two rolls is forced to enter the fibers of the paper to fix the text or image.
6. Preparation process
During the transfer process, when the toner is transferred from the surface of the photosensitive drum to the printing paper, some or more toner remains on the surface of the photosensitive drum, and the rubber scraper on the photosensitive drum collects the residual powder. The powder bin keeps the top of the photosensitive drum clean, and the photosensitive drum passes through the charging process after a rotation cycle to start the next cycle.
Second, the drum assembly (toner cartridge)
Regeneration process technology is utilized to increase the utilization of the drum assembly (toner cartridge). While reducing the printing cost, without changing the performance of the drum assembly, it is necessary to understand the wear characteristics of each component and the relationship between them and the mutual influence, so as to make a correct judgment according to the printed matter or the fault phenomenon.
According to the author's experience of more than 10 years, the cost of a regenerative drum assembly (toner cartridge) is less than 1/4 of the original product, and the service life is longer, allowing 3-5 times of filling, further saving printing costs. The economic benefit of the regenerative drum assembly (toner cartridge) is considerable, and the performance of the regenerated drum assembly (toner cartridge) after proper handling is normal. The following decomposition of the drum assembly (toner cartridge) is as follows:
1. Photosensitive drum
The photosensitive drum is an original part of the drum assembly (toner cartridge); the charging, exposure, development, transfer, fixing and preparation of the laser printer work around the photosensitive drum; the photosensitive drum is consumed by the laser printer Material, a photosensitive drum, its service life is generally about 6000-10000 sheets, for the drum assembly (toner cartridge), the toner cartridge is consumable material (but some toner cartridges can be thought of with ink) The price of the new drum kit (toner cartridge) is about 1/10 of that of the whole machine. If you frequently print the sulfuric acid paper and print the paper, replace the drum kit (toner cartridge) for 3-6 months. The amount of the cost may reach or exceed the price of a complete machine.
Some laser printers are designed with the photosensitive drum and toner integrated, which makes it difficult to replace the drum and the toner; if it is properly maintained and used, a drum kit (toner cartridge) can be changed to the drum or powder for 3-5 times. .
Among the components of the regenerative drum assembly, the main components to be considered are: photosensitive drum, cleaning blade, developing roller, primary charging roller, and the like. These components work together in the drum assembly to produce good print results and improper handling. It also affects the cycle of use.
There are three main types of drum wear:
1 partial defect. It means that a part of the black conductive layer outside the aluminum of the photosensitive drum has a defect, and the photosensitive drum cannot be used any more.
2 comprehensive wear and tear. It means that the photosensitive layer of the photosensitive drum is "aged" and can be used until the surface of the photosensitive drum cannot be charged and the printed matter has a bottom ash.
3 groove wear. It means that the drum is "scratched" and forms grooves or grooves for various reasons.
In order to reduce the wear of the drum, a layer of toner and talcum powder can be placed on the drum before the new drum is used or after the drum is cleaned. When a new original drum kit (toner cartridge) is unpacked, It can be noted that it uses a liquid lubricant which has been tested to reduce the wear rate of the photosensitive drum by about 30%.
In order to reduce the unnecessary wear of the drum and prolong the service life, the following problems must be noted:
1 The photosensitive drum is a silicone photoconductor, which works for a long time and has fatigue problems on the drum surface. At work, I recommend that the conditional unit be used interchangeably with 2 drum components (toner cartridges), and the cross-use time is preferably one week.
2 When printing about 6000-10000 sheets, it is found that the ink and image of the printed product are light and uneven, and after the reasons such as transfer electrode and toner are excluded, the life of the photosensitive drum is terminated and should be replaced.
3 The replaced photosensitive drum can easily handle the photosensitive surface of the drum surface when the drum surface is not damaged. The method is to use 3-5g of chromium trioxide, and directly wipe the chromic oxide with cotton wool in the direction of the photosensitive drum shaft, and wipe it once and without any omission.
4 Pay attention to the toner consumption and number of prints in the drum kit (toner cartridge). When the toner is low or there is no toner, it is very unfavorable to the drum.
5 In order to avoid damage to the photosensitive drum by rough paper, it is best to use offset paper within 70g-120g for printing paper. Because the offset paper is coated with paint layer during the papermaking process, the uneven surface of the paper surface is filled. The paper to be used is preferably sealed with kraft paper or placed in a plastic bag and cannot be scattered to prevent the paper from getting wet.
6 In order to avoid the damage of the photosensitive drum by powder, granules and paper dust, when the new toner is filled in the powder supply chamber of the drum assembly, the residual toner, granules, paper dust, etc. in the powder supply bin must be blown off. .
2. Drum (developing roller)
The drum is located above the powder supply bin, the center of the drum is a fixed permanent magnet, and the outer surface of the fixed magnet is a rotating metal sleeve. The magnet has four magnetic poles of N1, N2, S1 and S2, and the four magnetic poles have different Magnetic strength. Among them, N2 and S2 are responsible for carrying toner, N1 is responsible for stacking toner, S1 is responsible for developing work, etc. There are DC high voltage and AC high voltage on the sleeve. When the drum is working, the friction between the toner ions and the surface of the sleeve and the friction of the other toner particles are negatively charged. At the moment of negative half cycle of the alternating current, the toner particles are repelled at the developing pole S1 from the sleeve. Was pushed to the drum. The latent image area on the photosensitive drum has sufficient attraction to the toner particles, and the toner is no longer returned to the sleeve, thereby completing the development process.
The solution to the problem with the drum is as follows:
2.1 Print density is reduced. Mainly the aging of the black conductive layer on the metal sleeve outside the drum. When using the regenerative drum kit (toner cartridge), increase the print density (as in the original product) and replace the attenuated black roller sleeve.
2.2 The concentration of the ink is lowered. At CanonLBP-
The black conductive layer of the BX type printer developing roller is worn faster because the toner cartridge is provided with a charging pad, which functions to control the amount of toner on the surface of the drum and increase the charge of the toner by increasing the friction. the amount. However, the friction of the charging sheet accelerates the wear of the black conductive layer of the drum, so that the refilled toner cartridge is significantly reduced in the blackness of printing. To ensure the printing effect, one is to replace the magnetic roller sleeve or apply a black conductive layer to overcome The above drawbacks, the second is to replace the new drum, not to try.
3. Cleaning blade
The cleaning blade is made of rubber. A soft, transparent sheet. Its function is to scrape off the residual toner on the drum, so that the surface of the drum is uniformly maintained with a charge of -100v. In the work, how to identify the quality of the cleaning blade, whether to continue to use is summarized as follows:
3.1 After the cleaning blade has been used for a long time, the color of the blade becomes amber, and it becomes hard and brittle. Replace the new blade to avoid scratching the drum due to hardness.
3.2 The cleaning blade is damaged and warped due to aging, and a new blade must be replaced.
4. Charging roller
The charging roller is composed of a metal shaft, a conductive foam rubber layer, a resistance layer, and a protective layer. The conductive rubber layer provides both a charging circuit and a pressure of the charging roller on the surface of the photosensitive drum, and the resistance layer functions to limit the charging current from the charging roller to the photosensitive drum. The function of the charging roller is to erase the electronic characters and images remaining on the photosensitive drum and charge the drum surface with a charge of -100V. During operation, a DC high voltage and an AC high voltage are applied between the charging roller and the photosensitive drum, both of which represent superposition. At the peak of the AC, the charging roller transfers the charge to the photosensitive drum to form a strip-shaped charging zone. The density of the ribbon charging zone distributed on the photosensitive drum depends on the frequency of the alternating current. In other words, the higher the printing speed, the higher the frequency required for the AC voltage.
In the regenerative drum assembly (toner cartridge), the charging roller is one of the important components and a relatively sensitive component. The following faults caused by the charging roller are summarized as follows:
4.1 The prints have a light gray bottom ash and a ghost image. The main reasons are: A. The protective layer of the charging roller is damaged, which affects its moisture-proof and chemical-proof properties, resulting in a decrease in charging effect; B. Conductive layer, resistive layer, and protective layer of the charging roller are electrically conductive. Poor performance; C. The market purchases rough, uneven charging roller and sticky charging roller surface to accumulate toner particles, paper dust, etc. to reduce charging effect; D. fixing roller contamination; E. If ghosting occurs before the fixing roller The malfunction occurs during the imaging process caused by the charging roller or the photosensitive drum.
4.2 Vertical marks appearing on the printed product, repeated black spots are: A. There is a small pit in the charging roller, the toner is trapped and filled up after the small pit, and it is contaminated onto the photosensitive drum; B. If the charging roller is intact, it can be removed from the photosensitive drum. , fixing roller and other aspects of inspection.
4.3 printed products produce horizontal black line: the replacement charging roller has no patented resistance layer, the DC current is large, and the horizontal black line phenomenon is easy to occur, causing damage to the photosensitive drum.