Often the cause of cartridge malfunction is wear of its main components - the photoreceptor drum, cleaning blade, magnetic shaft, dispensing blade and primary charge shaft. Malfunctions can also be caused by the repair blade, contacts, pins, drum curtains, and even the housing itself, in general terms. And now, a little more about each of the problems.
Photoreceptor drum
Most often, the photo roller is responsible for cartridge failure. The toner is removed from it with a cleaning blade, and paper also comes into contact with it during the printing process, which greatly affects the condition of the protective layer. Typically, if the photoreceptor drum is damaged during printing, the following symptoms appear:
1) A straight, very thin line means the drum is scratched.
2) Groups of dots repeated throughout the entire page indicate a chip on the drum. The distance between the points corresponds to the circumference of the drum.
3) Gray toner marks on the page. The reason is an overexposed drum. The distance between spots depends on the circumference of the drum.
4) Gray "tire tracks" on either the left or right edge of the page. This is sometimes called "wind-blown sand." This defect is caused by wear on the drum.
In all of the above cases, the drum should be replaced. There is no reliable way to repair a damaged photo roller surface.
Cleaning blade (squeegee)
The cleaning blade removes any remaining toner from the surface of the photoreceptor drum.
The following signs of breakdowns are usually encountered:
1) A 3.2mm thick gray line along the entire page is caused by a cut or worn blade.
2) Gray page, toner build-up on the drum - caused by a very old, dull blade. Such blades cannot be reused.
3) The cleaning blade "jumps" and therefore damages the drum. This means that not enough lubrication has been applied to the blade. If such a defect is found, the cleaning blade should be replaced. A poorly lubricated squeegee can also “stick” to the drum if not used for a while.
Magnetic roller (HP/Canon cartridges)
The magnetic roller is a specially coated aluminum roller that transfers toner from the toner supply compartment to the drum unit. The main problems occur due to scratches or wear.
1) Light print. The main cause of this defect is wear of the magnetic shaft, because Over time, the black conductive coating on the shaft will wear off. If, during a visual inspection of the shaft, you notice a silver core, it means the shaft is worn out and requires replacement. This problem mainly occurs when printing solid black areas. Simple text will be printed without noticeable defects.
2) White spots on the page may appear if there are scratches on the coating. Usually one or two scratches do not cause problems, but if there are more, white spots will appear when printing. This is especially noticeable if the scratches are concentrated in one specific place.
3) Intermittent printing - this defect in image transmission occurs when the contact of the magnetic shaft is faulty. This results in light-colored or blank pages.
4) Large gray spots that repeat with each revolution of the shaft - the cause of the problem is a static discharge on the shell of the magnetic shaft. Static discharge can be caused by using a vacuum cleaner, for example, while refilling a cartridge when the humidity is below 40%. The only way to get rid of the charge is to wipe the shaft with a special cleaning agent.
Development roller (Samsung/Xerox cartridges)
The development roller is a roller consisting of a metal core covered with molded rubber with a conductive coating. The toner is held on the developing roller by constant voltage from a high-voltage power source. In this case, no magnets are used to attract toner. The main problems occur due to scratches or wear of the conductive coating. All toner is abrasive, and as the pressure of the metering blade forces it against the surface of the developer roller, it can cause wear on the developer roller.
Magnetic shaft - problems usually occur
similar to problems with the magnetic shaft of HP/Canon cartridges (see point above).
Primary charge shaft
The primary charge shaft performs two functions. First, it places a permanent charge on the surface of the drum, which allows the laser beam to create an image on it. Second, it places an alternating charge on the photoroll, which helps wipe away any residual charges remaining on the surface. Because of this dual role, many serious problems occur with the primary charge shaft.
The following problems usually occur:
1)
“Blurring” of the image - this defect manifests itself in the fact that an image printed, for example, at the top of the page will be less clearly repeated below. This happens when the outer covering of the primary charge shaft is worn or dirty.
2) Vertical stripes - caused by wear on the outer coating of the primary charge shaft.
3) Background - the reasons are similar to the previous two.
4) Horizontal stripes— this defect is caused by contamination of the contacts of the primary charge shaft.
5) Black spots on the sheet - This problem is caused by scratches on the primary charge shaft. The spots appear at a distance equal to the circumference of the shaft.
6) Random dots on the page are a problem caused by too much powder on the primary charge roller. There may be black spots on white areas and white spots on black areas.
Feed roller (Samsung/Xerox cartridges)
The toner, mixed in the hopper using a stirrer and receiving a triboelectric charge, is transferred to the toner supply shaft, which is energized. Further, due to the potential difference, the toner is transferred to the development shaft.
Measuring blade (HP/Canon cartridges)
The metering blade controls the amount of toner on the magnetic roller. A worn blade will result in light-colored printing, and the blade will create grooves on the surface of the roller, causing streaks (white voids) to appear along the entire page.
Dispensing blade (Samsung/Xerox cartridges)
The metering blade controls the amount of toner on the development roller. A worn blade will lead to the same consequences as in the case of HP/Canon.
Recovery Blade
The recovery blade directs the toner removed from the drum into the waste toner hopper. A damaged blade will cause dots to appear all over the page, and this defect will only get worse over time. This phenomenon is caused by toner spillage. Most often, the cleaning blade becomes damaged (crumpled) during recovery, and toner begins to accumulate on the surface of the blade and fall off from there. The longer a cartridge prints with a bent blade, the more toner accumulates on it and spills into the cartridge. If a cartridge is returned to you with this problem, you should carefully disassemble it and examine the recovery blade.
In printers that print laser technology, cartridges are an integral part of the image reproduction system. Almost 70% of all the parts involved in creating the print are concentrated in a replaceable block filled with a coloring composition.
Structural elements of the cartridge
In general, a replaceable unit is a sealed hopper with a compartment containing a coloring composition - black, red, yellow or blue and uh electromechanical parts for creating an impression. There are two types of replacement devices for laser printers, with or without a built-in image drum. In the second case, the photosensitive shaft is installed in the printer body and the operating time of the drum increases significantly.
Rice. 1 Main details laser cartridge
Toner Bin Parts and Structures
In this compartment, in addition to the powder itself, there are elements for applying paint to the surface of the photo cylinder. This:
- magnetic roller;
- knife for dispensing the coloring composition;
- a blade that seals the junction of the magnetic shaft and the housing;
- activator for mixing toner and maintaining the recommended density.
MagRoller(magnetic roller). It is made either of an aluminum tube with a protective coating and a magnetic rod inside, or of dense rubber with magnetic properties. The shaft is secured to the housing walls with bushings, allowing it to rotate freely.
The magnetic field, attracting metallized paint particles, provides the toner with a negative charge. A smooth surface of the shaft is the key to high-quality printing.
Doctor Blade(toner dispenser). A rectangular metal frame, the length of which corresponds to the dimensions of the magnetizing roller, equipped with a flexible plate. The plate material can be metal or polyurethane.
The purpose of the dispensing knife is to leave exactly as much toner on the magnetic roller as is needed for printing on at this stage. Wear on the blade affects the quality of the prints, the metal flexible plate can get scratched or chipped, polyurethane lasts longer, but still becomes thinner over time and dispenses worse. Regular cleaning of the dosing plate or its timely replacement in case of severe wear will restore print quality.
Mag Roller Sealing Blade(sealing blade). It is made of flexible materials that do not damage the surface of the magnetic shaft. Most often, it is polyurethane.
After the toner is transferred to the photoreceptor, the part of it that was unclaimed for developing the design remains on the surface of the magnetic roll. The sealing blade removes remaining ink and leaves it in the toner compartment for reuse.
Toner Agitator Bar(activator frame). Metal rotating frame. Prevents coloring powder from sticking and clumping. Optimal density toner is easily and evenly attracted to the magnetic roller.
Toner(toner). Fine powder made from polymers or waxes. Color is given by appropriate pigments, and to obtain magnetic properties it is treated with metal oxides.
Waste toner compartment
This section is where the image is exposed and developed. Essential elements:
- photo drum;
- coronator;
- drum cleaning blade;
- toner pick blade.
OrganicPhoto Conductor (OPC) Dram(photo drum). The main element of image reproduction. It is made in the form of a hollow cylinder coated with an organic photosensitive film or zinc oxide, which has a photoconductive effect.
The negatively charged photoreceptor is irradiated with a laser beam. The image is exposed by a programmer; in the areas that reproduce the image, the laser neutralizes the negative charge. As a result of exposure, toner from the magnetic roller is attracted to these areas.
The lifespan of the photosensitive film is short, so this part has to be changed frequently. Drums with a metal coating are more durable, but are also susceptible to exposure or deformation if not used carefully.
PrimaryCharge Roller ( primary charge shaft). It is made in the form of a shaft with an elastic coating; inside there is a conductor that allows corona discharge to pass through.
The task of the corona meter is to uniformly charge the surface of the photocylinder with a negative charge. Before starting work, the photodrum has no polarity, that is, its surface is a dielectric. The passage of the discharge creates an electric field around the primary charge shaft, which, acting on the photosensitive surface of the photodrum, gives it a negative charge.
It is the work of the coronator that is accompanied by the release of ozone. After transferring the image to paper and cleaning the photodrum from toner residues, the corotron again comes into action to remove the programmed image from the photocylinder.
WiperBlade(cleaning knife, squeegee). The knife is made in the form of a light metal plate with a glued rubber or polyurethane blade.
Not all of the toner ends up on the sheet of paper; some of it remains on the photoconductor. The viper removes the remaining paint composition into the waste compartment.
RecoveryBlade(picking blade). Made from polyurethane. Designed to prevent toner removed by the squeegee from getting onto the paper.
|
Cartridge |
Primary charge shaft |
Image drum |
Magnetic shaft |
||
Principles of interaction of cartridge elements during printing
The cartridge is the first to start working when the “print” signal is given. The following actions occur.
Rice. 2 Scheme of operation of a cartridge in a laser printer
- Treatment of the photodrum with a corona treatment (PCR) to impart negative polarity to the surface of the cylinder.
- Turning on the laser unit located in the printer body. The laser, controlled by the programmer, removes part of the charge from those points of the photoreagent surface of the cylinder where the image is programmed. This process is called exposure. The result is a complex of point charges with different levels of polarity. More strongly negatively charged points on the surface will repel similarly charged toner. Accordingly, the exposed parts of the surface will attract paint and specified image will appear.
- In parallel with the operation of the laser, the magnetic shaft is turned on. It attracts toner from the hopper and gives it negative polarity. The interaction of the fields of the magnetic shaft and the photodrum promotes the transfer of ink powder to the photosensitive surface. Turning off the device at this point in operation will allow you to examine the pattern printed on the photo cylinder. This method is used to diagnose wear on the surface of the photodrum.
- From the photoconductor, the image is transferred to the supplied sheet of paper. The sheet is first pulled through rollers that give it a positive polarity. The image formed by the negatively charged toner on the surface of the drum is deposited on the paper. To secure text and pictures, paper sheet pulled through heated rollers that melt the toner.
- The next step is to clean the photo cylinder from any remaining paint. The procedure is performed with a cleaning knife.
- Next, the coronator removes the previous exposed image and prepares the photoconductor for the next printing step.
After restoring the original data, the process is repeated. Printing one sheet of A4 format may include several sequential text transfer processes.
Equipping laser cartridges with chips
Currently, all manufacturers equip replacement units for printers with programmable modules - CHIPs. The presence of such accessories in cartridges has both positive and negative sides.
What's good about CHIPs?
- The amount of unused toner is recorded.
- The volume of used paint returned to the waste compartment is determined.
- Interact with the automatic calibration system of the device. The system monitors color purity and print quality.
- An optical system located in the cartridge writes data to the module.
Rice. 3 Color laser cartridges
What's wrong with CHIPs?
- Can be programmed to a certain amount of printed sheets or even drum rotations.
- After the message about the end of the toner, the connection with the calibration system is broken. An accompanying background appears on the prints and color rendering in color printers decreases.
- Some modules can only work with certain printer models and cartridges. For example, in a color laser printer you cannot change the chips on the cartridges from a red to a green or black block.
- Contactless radio chips are difficult to detect and replace.
- After the ink runs out, the CHIP may block the printer.
- Non-reprogrammable CHIPs are quite expensive.
Customers should not blame the greed of the company that refills cartridges. In addition to the cost of toner, it is necessary to replace some parts that have undergone significant wear or deformation during extreme use. But, the most significant part of the cost of refilling is programmable modules.
One of the most important parts and at the same time the main consumable material in a laser printer is its cartridge. Structurally, a laser printer cartridge is not so simple device, as it seems at first.
It usually consists of the following parts: photo roller, squeegee, magnetic roller, metering blade and charge roller. In addition, not all cartridges are similar to each other; the fact is that Brother Samsung and Xerox consumables, unlike HP and Canon, use non-magnetic toner, and instead of a magnetic roller they are equipped with a rubber dosage roller. It should also be added that the consumables of these three companies do not have a waste hopper and the dosing blade in them is made of metal.
A part of the cartridges, such as a squeegee, is a metal frame, the edge of which is equipped with a special cleaning element that has good elasticity. The main purpose of this part is to remove the toner that remains after transferring the image onto a sheet of paper.
It should be noted that the squeegee has approximately the same service life as the photodrum. Consequently, the squeegee is changed, as a rule, simultaneously with the photo roller. This part has a felt toner seal, thanks to which the toner does not spill out of the waste hopper.
Samsung cartridges deserve special attention. The fact is that, as a rule, they do not have a squeegee - the so-called squeegee is used instead. primary charge roller, which is cleaned with a special brush.
Mining bunker
A part such as a waste toner bin is a part of the cartridge designed to store waste powder. The latter gets there after being cleaned from the photodrum. Each time you refill, this container must be cleaned.
Photoreceptor
First you need to answer the following question: what is a photoconductor? This type of part for cartridges is an ultra-sensitive “heart”, which is a hollow cylinder made from aluminum. The top of this product is covered with a dielectric layer.
The photoreceptor can be located both in the printer itself and in its cartridge. On some devices, for example, on equipment Brother cartridge consists of two parts - toner and drum. One part contains the image drum, and the other contains the toner. They change independently of each other as they wear out.
The function of photo drums is as follows: after sending a sheet of paper for printing, the primary charge shaft, pressed against the photo roll, transfers to it a charge with a minus sign and, at the same time, the ability to repel toner particles (powder in the cartridge). All those areas that were marked by the laser beam change their charge to positive, as a result of which they attract the toner. Thus, the photo roll forms a visible imprint of the image sent for printing.
At the finish, the paper with toner adhering to its surface passes through a high-temperature oven, which makes it possible to securely fix the toner on the sheet. In general, the photo roller is the most capricious, but at the same time expensive part of a laser printer of any model. As a rule, you should not touch it, as this can lead to a sharp deterioration in the quality of subsequent printing.
Corotron
A corotron is a thin wire to which high voltage is applied. The purpose of this part is to transfer charge, resulting in the release of a certain amount of ozone. Using a corona meter, the surface of the photodrum is electrified, on the surface of which, in turn, a primary charge appears. Corotrons in the form of wire were used in almost all analog copiers, but now they are used much less often than before. Many manufacturers have switched to using charge rollers. But even today, wire corona wires are installed in Brother printers and MFPs.
Infection roller
The charge shaft is a product consisting of a metal core enclosed in a rubber shell. The main task of this part is to charge the photodrum with particles with a negative charge. In addition, the primary charge shaft in Samsung cartridges also serves to clean the photodrums of all kinds of debris.
Photo roll curtain
This part of the cartridge serves for protective purposes so that the photodrum located inside the cartridge is not damaged during transportation. It protects it from dust and other negative factors. When the cartridge is installed in the printer, the shutter opens and allows the device's laser to freely charge the photoreceptor. Therefore, to access the photo roll when you have removed the cartridge from the device, you first need to remove this protective shutter.
This element of the cartridge is designed to uniformly transfer toner microparticles to the surface of the photo roller. The magnetic shaft is made, as a rule, in the form of a hollow tube containing a magnetic core. At the same time, in Samsung consumables, the magnetic shaft is called “Developer Roller” and consists of a composition whose properties resemble high-quality rubber. There is also the so-called. magnetic shaft bushings, which are plastic bushings that set the gap between the magnetic shaft and the photoreceptor.
Dosage blade
A part called the dispensing blade is designed to create an even layer of toner on the magnetic roller. For its manufacture, metal or plastic with good elasticity is used. In addition to mechanical wear, the metering blade is also susceptible to dirt. For this reason, it must be regularly and thoroughly cleaned of any foreign particles. In addition, the dosing blade has a smooth surface, which is necessary in order to ensure even distribution of the colorant.
Chip
Such an important part of a laser printer as the cartridge chip is capable of reading the number of printed sheets of paper. It is a small flash memory that is filled with information related to the operation of this consumable. For example, the chip contains information about serial number cartridge, as well as its type and date of manufacture. Thus, the chip on the cartridge is a kind of “passport”, especially since it can warn the user that the toner has run out.
And on Xerox printers and the Samsung chip may completely block further operation of the device if the chip informs it that the toner has run out. And in order to refill a cartridge with such a chip, you will either need to change it or reflash the device itself. Users of HP and Canon printers do not have such problems - the device will tell them that consumables ended, but the chip will not stop operating the device.
Thus, the design of a laser model printer cartridge is quite complex. The main thing is not to forget that the photodrum for the cartridge in this case is its main element, and therefore when refilling it should be handled with the utmost care. An important difference between cartridges designed for a laser printer and an inkjet printer is that they are easier to refill and, if necessary, you can change any part in them. And this despite the fact that they are not intended by the manufacturer either for disassembly or refueling. At the same time, with a competent and responsible approach, you can disassemble such a cartridge yourself, without resorting to the help of specialists.
The photoreceptor charging system using a roller compared to a system using a corotron for this purpose has noticeable advantages: almost complete absence of ozone emission, less dependence on conditions environment, quite high stability of the charging current. However, nothing in this world is perfect, so you have to deal with problems caused by these videos quite often in life.
The article discusses typical faults in monochrome laser printers HP/Canon, which are caused by charge rollers, recommendations are given for cleaning them and determining the need for replacement, problems that may arise when using compatible PCRs are described, and ways to solve them.
Charge roller, aka Primary Charge Roller (PCR) , aka primary charge shaft, aka “cartridge rubber shaft”, aka “cartridge corotron” (the author really doesn’t like the last term when applied to PCR, but people use it so often that you can turn a blind eye to the fact that the corotron, by definition, must have a corona discharge) performs two functions in the cartridge - charging the surface of the drum and erasing the residual latent electrostatic image. For this purpose, a high voltage is supplied to the PCR, having a DC and an AC component. This leads to two main problems that can be caused by a faulty PCR - insufficient charge of the drum surface and insufficient erasure of the afterimage. The main reasons for this are usually the following:
- Contamination of the roller surface.
- Electrical breakdown of the roller material.
- Detachment of the outer shell (“stocking”) of the roller from the porous inner part.
- Punctures and tears on the surface.
- Surface wear.
- Detachment of the roller material from the metal axis.
- Change in electrostatic characteristics (dielectric constant, electrical conductivity) of the roller material.
Apart from dots and spots on the surface of the roller, repeated on the print at intervals equal to the circumference of the charge roller, then the most common manifestation of a faulty PCR is repeat image . IN English language this defect is called " "(from the word "ghost" - ghost). To distinguish this defect from the very similar fusing offset, which is caused by insufficient fixation of the toner by the fixing unit, two main methods are used. The first is the measurement of the interval from the main image to the repeat - it should correspond to the circumference of the drum, and not the circumference of the fixation block shafts. The second is when printing stops at the moment when a sheet of paper is between the drum and the oven - if the repetition is already present on the unfixed image, then the reason is not in the oven.
At the initial stage of the roller failure, many people do not see the image repeat, because it is noticeable only in areas with a solid gray fill (and appears at an interval equal to the circumference of the charge roller or drum). This feature can be used for “early diagnostics” by printing a special test page similar to the one shown in the figure (for correct diagnostics, there should be several more pages in the job before this page with more uniform filling).
Here, in the gray areas, you can see a faint repetition of the letter "G" located at the top of the page. One or two faint repeats on a given page are normal; more clear repeats at the charge roller or drum interval indicate a problem with the charge roller.
If the charge roller performs the function of erasing the afterimage very poorly, then the repetition becomes noticeable in the white areas. An example is shown in the figure. In very rare cases, the cause of this problem is a drum failure.
Elimination method– make sure there is stable contact on the charge roller, to do this, clean the PCR sliding contact from dirty grease and apply a thin layer of fresh conductive lubricant (for example, OIL---SC-CONLUBE), clean the charge roller (on how to properly clean, described below), did not help - replace the roller.
Other common problem – background caused by insufficient charge on the drum surface. Since this problem has many other causes, its localization should be carried out using the “halving method”, i.e. by substituting a known good half of another cartridge into the phonating cartridge, etc. After we have found out that the reason is PCR, we do the same as in the previous case.
Below is an example of printing in the case of detachment of the outer “stocking” of the charge roller from the internal porous filler. No amount of cleaning or restoring contacts will help in this case - the PCR needs to be changed.
The charge rollers inevitably become dirty during operation. One source of contamination is very small particles of toner additives (for example, amorphous silicon, often used as an additive that regulates the charge and fluidity of toner) that cannot be completely removed with a squeegee. These particles, together with paper and other dust, create a whitish coating on the PCR, which prevents the roller from performing its functions normally. Accordingly, before reuse it needs to be cleaned, but it is important not to damage the roller by cleaning, which, as practice shows, is very easy to do.
For cleaning original charge rollers in HP/Canon monochrome cartridges(except 35A, 36A and similar Canon) We do not recommend the use of any cleaner other than a lint-free cloth dampened generously with distilled water.. Alternative opinions on this matter related to the use of “Platenclene”, “Mr. Muscle”, etc. exist, but we cannot clearly confirm their effectiveness or harmfulness, so we simply DO NOT RECOMMEND it.
When cleaning, ensure that the roller surface is uniformly gray or black, free of whitish areas and toner adhesion. In this case, you should not put too much pressure on the roller, so as not to cause peeling of the outer shell. If after such cleaning there are indelible toner build-ups left on the roller, then you should think about the reasons for their appearance. Does the squeegee clean well? Is the toner collecting dust in the developing area? Something else? In our opinion, it is better to replace such a roller and eliminate the cause of its excessive contamination. For a comment on an alternative point of view, see just above.
Another point worth paying attention to is that in modern HP/Canon cartridges there are several types of charge rollers. Rollers of one of these varieties (let's call them “lipped”) are potentially prone to rapid failure. Their feature, which is clearly visible visually, is that the outer shell at the ends protrudes several millimeters beyond the internal porous filler. If you squeeze the edge of such a roller, you can see that the shell is easily separated from the central part.
"Lipped" PCR
The shell of the “lipped” PCR moves away from the inner part when compressed
Our recommendation for these types of rollers is to replace them immediately after the original cycle, because there is no guarantee that they will survive the next cycle to the end (even their own ones do not always survive). If you risk leaving such a roller in the cartridge, then it should be cleaned very gently, since even a small force can damage it.
Not all original charge rollers are so prone to failure. There are varieties that can work several cycles without problems, but, unfortunately, they are becoming less and less common. Below is what a “normal” original PCR looks like.
The shell of a "normal" PCR is cut flush with the inside
The shell of a “normal” PCR does not move away from the inside when compressed
Closed-end PCR is also "normal"
"Once the decision is made to replace the charge roller with a compatible one, there is a chance to encounter problems caused by differences in the production technology of compatible PCRs from the original ones.
Many manufacturers' rollers have an outer shell that is significantly thinner than the original. In addition, they have the same problem as the “lipped” original PCRs - the “stocking” easily peels off from the inner filler. Shown below appearance such videos. Usually these rollers work fine for one cycle, then depending on your luck.
The next type of compatible PCR is the so-called "hard" rollers. They are manufactured by SCC. Their peculiarity is that they are made of a more rigid material than the original ones. On the one hand, this is good, because... The service life of these rollers is high and they can be cleaned without thinking too much about the force with which we press on the surface of the roller.
"Hard" PCR produced by SCC
But they also have a negative point. When using “hard” PCR printers with print speeds of more than 10 ppm. the transformer in the high-voltage power supply begins to emit a clearly audible squeak. This squeak does not affect the performance of the printer in any way, but many users do not like it. In order to minimize this problem, SCC suggests using special rollers in conjunction with these rollers. drums with “noise-reducing insert” inside. The insert is a heavy plastic tube glued inside the drum.
“Noise-reducing” insert
This solution does not eliminate the squeak completely, but makes it noticeably quieter, which is acceptable for most users.
Such drums can also be used in conjunction with “soft” charge rollers without any negative consequences.
The latest solution to replace PCR, devoid of the disadvantages described above, appeared not so long ago. “Soft” SCC Odyssey® charge rollers do not cause unnecessary noise and at the same time have a fairly long service life.
"Soft" PCR SCC Odyssey®
In conclusion, here are the order codes for the most popular items mentioned in the article.
PCR-HP-LJ1200-SC-OS-SOFT– “Soft” SCC Odyssey® charge roller for Q2612A, C4092A, Q2624A/X, C7115A/X, Q2613A/X, C3906A and similar cartridges Canon cartridges. This roller is not yet qualified for use in Q5949A/X and Q7553A/X cartridges in low humidity environments.
PCR-HP-LJ2100-SC-OS-SOFT– “Soft” SCC Odyssey® charge roller for C4096A, Q2610A, Q6511A/X, C4127A/X, C8061A/X, Q1338A, Q1339A, Q5942A/X, Q5945A, Q7551A/X cartridges.
PCR-HP-LJ5L-SC– “Hard” SCC charge roller for Q2612A, C4092A, Q2624A/X, C7115A/X, Q2613A/X, C3906A, Q5949A/X, Q7553A/X and similar Canon cartridges. When installing these rollers, do not forget about the need to use drums with a noise-reducing insert.
DRUM-HP-LJ1010-SC-V3-INSERT– drum with noise-reducing insert for Q2612A cartridges.
DRUM-HP-LJ1200-SC-V3-INSERT– drum with noise-reducing insert for cartridges 2624A/X, C7115A/X, Q2613A/X.
DRUM-HP-LJP2015-SC-INSERT– drum with noise-reducing insert for cartridges Q5949A/X, Q7553A/X.
There are two systems for charging the photoreceptor: using a corotron and using a PCR roller. The advantages of the second option are the high stability of the charging current, the almost complete absence of ozone emission and less dependence on environmental conditions.
The charge roller (PCR - Primary Charge Roller), or primary charge shaft, is a rubber part that is one of the most important elements of a laser cartridge. Its purpose is to charge the surface of the photodrum and erase the residual latent electrostatic image from it. The principle of operation of the roller is to supply it with constant and alternating current under high voltage.
Like the image drum, the charge rollers require periodic maintenance. When disassembling the cartridge from them, using a soft cloth, you need to remove the remains of toner additives (amorphous silicon) and dusty paper particles that the squeegee could not cope with. On average, the service life of these elements is determined by 30,000 printed pages. At the same time, charge rollers, like other parts of printing equipment, periodically fail. In some cases they can be repaired, in others they need to be replaced.
The main problems arise in connection with the charge roller performing its direct functions: insufficient charge of the surface of the photodrum and incomplete erasing of the residual image. This can be caused by several reasons:
Changing the permissible parameters of dielectric constant, electrical conductivity and other electrostatic characteristics of the roller material;
Detachment of the roller material from the metal axis;
Surface wear;
The presence of tears and punctures on the surface;
Detachment of the outer shell of the roller from the porous inner part;
Electrical breakdown of the roller material;
Surface contamination.
You can tell that the charge roller is out of order by regularly appearing spots, dots, stripes and other defects on the prints. For their “early” diagnosis and timely elimination, experts advise periodically printing a test page.
One of the most common defects indicating a malfunction of the PCR is considered image repetition, or ghosting, from the English. ghost (ghost). The repeat interval corresponds to the circumference of the drum and is present on the image that is not yet fixed, that is, before the sheet enters the fuser. In rare cases this problem due to a malfunction of the drum itself.
Unlike ghosting, fusing offset appears due to insufficient fixation of the toner by the fixing unit, and its interval corresponds to the circumference of the shafts of this unit. If the charge of the shaft is unsatisfactory, as well as for a number of other reasons, a background often appears on the sheet, distorting the original image.
The simplest repair is to wipe the roller with a soft cloth soaked in distilled water. There is an opinion that instead of water, you can use “Mr. Muscle”, Platenclene or an acetone solution for these purposes. To clean the roller, press lightly on the surface, carefully removing any adhering toner and whitish areas of paper dust. As a result, the surface should acquire a uniform gray or black color. If this trick does not help, you will have to resort to more serious actions.
If repeats or backgrounds consistently appear on your prints, you need to clean the sliding contact from contaminated conductive grease and apply a fresh layer, and then clean the roller surface using the above method. If the outer “stocking” has peeled off from the porous inner filler, cleaning does not bring a visible result, residues of unremoved toner constantly accumulate on the surface, you will have to completely change the roller along with the squeegee.
It is quite difficult to carry out high-quality surface cleaning, as well as other actions, without damaging the roller coating, so it is better to entrust such work to a specialist. Especially when it comes to replacing parts! The charge rollers of some manufacturers are initially designed for one cycle of operation, and therefore, after failure, it is pointless to repair them - it is better to simply replace them.
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