Charge transfer shaft. Photo roller, squeegee blade, dosing blade, magnetic roller and other laser cartridge parts

This price was given to us by a manager at one of the car dealerships. Yes, it was unusual in this era of technological advances to receive printouts with such defects. Note that we were looking at the class of car - SUV, priced from 500 thousand rubles. And the price list created the impression that this was not a car dealership, but some kind of eatery selling cheap goods. Nevertheless, we are grateful for this gift of fate and have collected common laser cartridge malfunctions in a short reference article.

In the article we present the most common defects that arise during the life of many cartridges. The article focuses on Hewlett-Packard. Firstly, this brand has been one of the top brands on the printing market for many years, secondly, refilling original HP cartridges has not yet been canceled - which is what many participants in both the SMB business and the SOHO market use.

Printout test sheet from Hewlett-Packard LaserJet 1100

This is what an ideal test sheet should look like. Of course, 99% of this is due to the original cartridge. Needless to say, legitimate suppliers of the consumables market have well-functioning production, and strict control over defects has long been at the highest level. Up to 2% of total production is negligible indicators for defects, which are laid down by the manufacturer. However, this does not mean that all other manufacturing suppliers do things cheaply and poorly. You can also safely work with alternative consumables without problems. It depends on the brand, its product control and, of course, the warranty. Considering that the cartridges are refilled and will continue to be refilled, you shouldn’t be surprised that after 5-7 refills streaks began to appear. This is due to time, the resource of spare parts, low-quality components, and sometimes the inattention of the master or a production failure.

Speaking about the practical side of this article, let's give an example:

Looking at such documents, the conclusion is drawn that the cartridge is empty, the charge roller is faulty, there is a gap between the magnetic shaft and the dosing blade, the photodrum that came with this cartridge from the very beginning will also need to be replaced. Anyone can have this ability to analyze printouts, regardless of status and position. Agree, is it nice to know a little more than everyone else and apply knowledge in practice? Then let's continue.

How the world of the cartridge works

This is how you can simplify the printing “players” within the cartridge

The photo shows components from the Hewlett-Packard q2612a cartridge. Although this principle of “constructing” HP cartridges is extended to almost all monochrome consumables. Top down:

• Squeegee (cleans toner from a drum that has not been used)
• Image drum (forms the primary image)
• Charge roller (charges and discharges charge from the photoconductor drum)

The photo is missing a magnetic shaft with a dispensing blade, which are responsible for transferring toner to the photoconductor. In total, this is a single development block. Some manufacturers have a separation between drum units (DRUM) and toner compartment. The HP company has gone its own “path”: whether it is good or bad cannot be said unequivocally. Let's move on from theory to the practical side of the material.

Malfunctions, consequences and combating them

Despite the small number of components, there are quite a lot of variations in poor quality printing. Let's go in order:

OPC (Organic Photo Conductor)

Photodrum, also known as drum, also known as photoreptor, photoconductor, photoshaft, OPC. Essentially, the toner pattern that is formed on it will subsequently be transferred to paper. Hence the nuances of his life.

There is a problem with the image drum of the Hewlett-Packard LaserJet 1200 cartridge.

The most common problem. Black patterns almost always appear at the edges of printouts. This is critical wear of the photoreceptor. The photosensitive layer has worn off, and the toner adheres to the “naked” substrate and is transferred to the paper.

This is how wear looks on the photoreceptor itself. Essentially, this is the physical process of rubbing off the coating on the paper and toner.

The solution to this problem, alas, is only to replace the drum. All articles and materials related to photocoating restoration do not show impressive results when the equipment is tested in practice. Although, we are sure that in a year or so the photoreptor can be restored almost at home.

Bad photocopies or printouts are not always caused by any component as such. Dirt, dust or coarse toner also often appears as marks on freshly baked work.

The dirt between the cleaning blade and the drum is quite noticeable

And it finds its manifestation on printouts

It can be easily fixed by rebuilding the cartridge. The easiest and fastest way is to completely replace the cartridge.

PCR (primary charge roller)

The second component of the printing system is PCR, aka corotron, aka primary charge roller, aka precharge shaft. This is a sponge roller that applies an initial charge to the drum (see description above) and removes the remaining charge at the end of the cycle. This charge shaft is a metal axle pressed into a rubber shell. The untidiness with which he can “reward” the printouts will always be noticeable.

It is impossible to distinguish a working PCR from a faulty one “at a glance”

But everything is visible on the printouts of the Canon LBP810

This component cannot be repaired. The problem can only be solved by replacement. The price for the HP line of such spare parts ranges from 1 to 20 US dollars, depending on the printer model.

Magnetic Roller

This shaft on HP printer solutions consists of a metal cylinder, the surface of which is covered with a special layer, and inside there is a magnetized “core” in the form of a rod. It rarely fails on its own. Mostly, dirty printing problems are related to toner dosing.

So the dirt “donates” a strip to the magnetic shaft, and, as a result, “takes away” the strip of the image on the printouts

One of the manifestations of incorrect dosage of powder is that toner is poured into the gap between the dosing blade and the magnetic shaft

The toner is poured onto a magnetic shaft, which, in turn, transfers it to the photodrum, which, as expected, according to all the rules, transfers it to paper. This is how you get inappropriate stripes along the sheet feed. They may appear black - if the gap has become larger than necessary for toner dispensing. Or, conversely, light, when dosing is difficult due to the fact that the gap is closed by dirt from inside the toner hopper.

In the office, this dirt could be anything... even a fly.

Solving the problem by sorting through the cartridge or completely replacing it with a known good one.

Bunker for mining

At the beginning of the article it was said that the cartridge system has a squeegee that cleans off toner that has not been used. This toner goes into a special compartment - a hopper. There it is collected and cleaned out during restoration or refueling. But, alas, sometimes bad toner or inattention during work bring unpredictable troubles.

An overfilled hopper spills toner outwards - this is immediately visible on printouts

The solution to the problem is cleaning the hopper or replacing the cartridge.

Taking a step aside, we would like to note that the cartridge components are not always to blame for problematic printing. For many users, a printer is a box that only knows how to print. But for all service engineers, a printer is a work of art. Even if he is the simplest personal “monochrome”. And before you scold consumables, you need to make sure that it is the cartridge that is to blame.

Exotic deviations in the hardware of the Hewlett-Packard LaserJet 1300 printer - unsuccessful replacement of thermal film resulted in moire around the letters

To determine which part of the printer is to blame for poor quality printing, you need to understand a little about printing technology and understand how it all works. For this purpose, there is a section on printers and consumables.

Of course, in search of the most common failures in the cartridge, you can go deeper into another 5-7 variations of bad printing. But this happens when the cartridge has recycled its resource not just once or twice, but ten times. Then the felt inserts will be erased, which will cause play in the magnetic shaft, and the squeegee will be at risk, and the toner will be added again. To prevent troubles from unexpectedly awaiting you, use high-quality consumables. The main thing is not to confuse the everyday situation when looking for an unusual breakdown:

If you use high-quality toner cartridges and update them regularly, they will not let you down. Remember that skimping on savings can be expensive. Agree that it’s not pleasant when you present a high-value product group to a client on materials that are crossed out length and breadth by the printer. What impression will a person have when he sees the price list with which this article began? And the cost of replacing the drum for that company would be only 500 rubles. When selling cars worth 500,000 rubles, such a nuance could have been eliminated, and not embarrassed in front of clients. Of course, there are situations when there is not enough cartridge life or it is not possible to send a courier for the next portion of printer consumables. But in general it is not our task to solve such organizational problems. Our goal was to technically analyze cartridge failures. That's what we did.

This is what printouts from printers should look like, regardless of brand and model. All of them are clear, contrasting and without a single blot. Ideal quality of document flow, which consists of the quality of each specific printout.

Conclusion

As stated in the latest advertising postulate from Hewlett-Packard - “Refilled cartridges are a headache. HP is the cure!” We would not say so categorically, but rather advise you to choose the right consumables or refilling and restoration company. Then there will be tangible savings and no headaches. Tested for years by many companies.

We hope that the article helped IT workers expand their theoretical knowledge and gain practical experience on what and how to correct when poor-quality printing occurs. Let's tell you a secret, the materials presented have a lot in common with color printing technology. Due to some specifics, it was decided to divide the material into monochrome and color printing. In the near future, expect articles on consumables of both an analytical and purely practical nature in relation to color laser printing.

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 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.

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 direct and alternating current at 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 is associated with 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.

There are two main compartments in the cartridge - the waste compartment and the toner compartment.

The main components of the mining compartment:

1 - Organic Photo Conductor(OPC) Drum, Drum (OPC, Drum, Photoreceptor). It is an aluminum cylinder coated with an organic photosensitive and photoconductive material that is capable of preserving the image created by the laser beam.

2 - Primary Charge Roller PCR (charging roller, primary charge roller). Provides a uniform negative charge to the drum.

3 - Wiper Blade Viper (Cleaning Blade, squeegee, cleaning blade). Clears the drum of any remaining toner that has not been transferred to the paper. Structurally, it is made in the form of a metal frame (Stamping) with a polyurethane plate (Blade) at the end.

4 - Recovery Blade. Covers the area between the drum and the mining hopper. The Recovery Blade passes toner remaining on the drum into the hopper, preventing toner from leaking in the opposite direction (from the hopper onto the paper).

TONER COMPARTMENT

Main components of the toner compartment:

1 - Magnetic Developer Roller Magnetic roller (Mag Roller, Developer Roller). It is made in the form of a rotating metal tube, inside of which there is a stationary magnetic core. The toner is attracted to the magnetic roller and, before being supplied to the drum, acquires a negative charge under the influence of direct/alternating voltage.

2 - Doctor Blade Doctor (Metering Blade). Provides uniform distribution of a thin layer of toner on the magnetic roller. Structurally, it is made in the form of a metal frame (Stamping) with a flexible plate (Blade) at the end.

3 - Mag Roller Sealing Blade A thin plate similar in function to the Recovery Blade. Covers the area between the magnetic roller and the toner supply compartment. The Mag Roller Sealing Blade allows toner remaining on the magnetic roller to flow into the compartment, preventing toner from leaking in the opposite direction (from the compartment to the outside).

4 - Toner Reservoir Toner bin. Inside this hopper is the “working” toner, that is, the one that will be transferred to the paper during the printing process. In addition, the Toner Agitator Bar is built into the hopper - a wire frame designed for mixing toner.

5 - Seal Seal. In the new cartridge, the toner hopper is covered with a special seal, which prevents toner from spilling during transportation of the cartridge. This seal is removed before use.

Laser printing principle

The figure below shows a cross-section of the cartridge. When you turn on the printer, all components of the cartridge begin to move - the cartridge is prepared for printing. This process is similar to the printing process, but the laser beam is not sent to the drum and the image is not formed. The cartridge components then stop and the printer enters the Ready state.

When you send an image to print, the following processes occur in the cartridge:

1. Charging the drum

PCR uniformly coats the surface of the rotating drum with a negative charge.

2. Overexposure

The negatively charged surface of the drum passes under the laser beam. The beam is focused on the drum and is activated only in those places where toner will subsequently be applied. Under the action of the laser, the photosensitive surface of the drum partially loses its negative charge. Thus, the laser deposits a prototype image on the drum in the form of a weakened negative charge.

3. Applying toner

At this stage, the prototype image on the drum is converted into a visible toner image, which will then be transferred to paper. The toner located near the magnetic roller is attracted to its surface under the action of a permanent magnet from which the core of the roller is made. When the magnetic shaft rotates, the toner located on its surface passes through a narrow gap formed by the doctor and the shaft. As a result, the toner on the magnetic roller becomes electrified, acquiring a negative charge. Negatively charged toner sticks to areas of the drum that have been exposed to light. The doctor also ensures the uniformity of the toner layer on the magnetic roller.

4. Transferring toner to paper

Continuing to rotate, the drum, on which the toner image has already been applied, comes into contact with the paper. On the reverse side, the paper comes into contact with the Transfer Roller, which carries a positive charge. As a result, negatively charged toner particles are attracted to the paper. The result is an image “sprinkled” with toner on paper.

5. Pin an image

The paper with the toner image “spread” moves further to the fixing mechanism. This mechanism consists of two contacting shafts, between which paper passes. The Lower Pressure Roller presses the paper against the Upper Fuser Roller. The top roller is heated, and upon contact with it, the toner particles melt and bake to the paper.

6. Cleaning the drum

Some toner does not transfer to the paper and remains on the drum. The drum needs to be cleaned of any remaining toner. This function is performed by the viper. All toner remaining on the drum is cleaned by a wiper into the waste bin. In this case, Recovery closes the area between the drum and the waste hopper, preventing toner from spilling onto the paper.

7. "Erasing" an image

At this stage, the prototype image applied by the laser beam is “erased” from the surface of the drum. PCR uniformly coats the surface of the drum with a negative charge, restoring the charge in those places where it was reduced by the laser. Any of the known cartridges includes several different blades, each of which performs an important and necessary function. Cleaning the photodrum, dispensing toner, and sealing the cartridge hoppers depend on the blades. During operation, any defect in any of the blades, be it the drum cleaning blade, the toner dispensing blade, or the magnetic roller sealing blade, can damage the cartridge.

Drum cleaning blade (Wiper blade)

The cleaning blade is used to clean the drum of any residual toner that was not transferred to the paper during the image transfer process. The quality of the surface of the cleaning blade, the sharpness of the edges and the exact dimensions are very important for the normal operation of the cartridge.

Toner dispensing blade (Doctor blade)

The polyurethane metering blade regulates the amount of toner delivered to the magnetic roller and triboelectrically charges the toner to ensure accurate image transfer to the drum. The surface finish of the dispensing blade, its rigidity and dimensional accuracy are important for the normal operation of the cartridge.

Magnetic shaft sealing blade

The magnetic roller sealing blade seals the toner hopper and prevents toner from spilling onto the paper. The sealing blade of the magnetic shaft is easily damaged during cartridge reconditioning and must be replaced in this case.

Drum sealing blade

The drum seal blade is used as a seal between the OPC drum and the waste toner bin to prevent toner from spilling onto the paper, causing a "splashing" effect when printing. The structure of the material, precise and correct dimensions, as well as the quality of the blade tip are important for the normal operation of the cartridge.

Primary Charge Roller (PCR)

The primary charge roller charges the drum with a uniform negative charge, wiping out the old charge.

Magnetic roller (MagRoll)

The roller, together with the toner dispensing blade, charges the toner with a negative charge and transfers it to the drum unit, thus playing a significant role in the image formation process. If the toner is not uniformly charged or applied uniformly to the surface of the magnetic roller, the result will be light printing and a change in print density. Constant wear of the magnetic shaft is one of the biggest problems for remanufacturers. The magnetic roller is the basis for the overall print quality and thus has a major impact on the overall performance of the cartridge.

The photoreceptor charging system using a roller has noticeable advantages over a system using a corotron for this purpose: almost complete absence of ozone generation, less dependence on environmental conditions, and fairly 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 malfunctions in HP/Canon monochrome laser printers that are caused by charge rollers, provides recommendations for cleaning them and determining the need for replacement, describes problems that may arise when using compatible PCRs, 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 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.

Another common problem is 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, it needs to be cleaned before reuse, 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. Below is the appearance of 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– SCC Odyssey® Soft Charge Roller for Q2612A, C4092A, Q2624A/X, C7115A/X, Q2613A/X, C3906A and similar 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.