It was a busy morning at the ink cartridge world in Aylesbury, which is part of nearly 200 chain stores in the UK that sell branded and refilled printer cartridges. This is a booming business. In the past five years, the store's turnover has doubled.

But the owner, Martin Dyckhoff, said that customers repeatedly complained to him: the branded inkjet cartridges they bought ran out of ink too quickly.

The sky-high price of printer ink-more expensive than vintage champagne-has been well proven. What is less known is that the amount of ink in ordinary ink cartridges has drastically reduced. Dyckhoff said: "Newer ink cartridges contain only a small fraction of similar products ten years ago." "The quantity may be minimal."

For example, the Epson T032 color ink cartridge (released in 2002) is the same size as Epson color T089 (released in 2008). But T032 contains 16 ml of ink, while T089 only contains 3.5 ml of ink. There is a similar situation with HP ink cartridges. Ten years ago, the best-selling HP ink cartridge had 42 milliliters of ink and sold for about £20. Today, a standard printer cartridge manufactured by HP may contain only 5 milliliters of ink, but it costs about 13 pounds.

Cut the HP inkjet cartridge and you will find what happened. Over the years, the size of the inner sponge that contains ink has gradually decreased. The rest of the cartridge is now just empty space. At the same time, in Epson ink cartridges, the size of ink cartridges has been systematically reduced.

"The strategy has always been to encourage consumers to make high-frequency purchases," said David Connet, editor of The Recycler, a trade magazine covering the remanufacturing industry. "Large printer manufacturers have reduced the amount of ink in cartridges, encrypted chip technology, and used aggressive marketing strategies to prevent refilling."

Chris Brooks, the technical director of the British Cartridge Remanufacturers Association's industry organization, is more blunt: "Large printer companies are doing their best to extract more and more cash from poor consumers in exchange for less ink."

Experts say that the worst value is color ink cartridges. All three leading manufacturers, including Canon, sell single tri-color ink cartridges—cyan, magenta, and yellow—usually with less than 2 milliliters of ink per color. "Their value is very low, because when one of the three colors runs out, the entire cartridge will stop working," Dyckhoff said. "We always recommend that people buy printers that have separate ink cartridges for each color."

The reduction in the amount of ink in the ink cartridge allows the manufacturer to offer an extraordinary new product called "XL" (Extra Large), but almost the same size as a standard ink cartridge. For example, the HP300 produced by HP contains 5 milliliters of black ink and costs about 13 pounds. It also produces HP300XL, which has more ink-about 16 milliliters-and sells for around £20-25. But the sizes of the two are almost the same. In fact, some manufacturers’ "XL" cartridges may contain less ink than standard cartridges released a few years ago.

XL cartridges are an "insult" to consumers. Patrick Stead of Environmental Business Products, a cartridge recycler, said: "HP sells half-full cartridges, then label them with'XL', fill them up, and then pay a higher price. Sale. The difference in manufacturing costs is a few cents. This is a shocking plagiarism."

Printer companies argue that they are squeezing consumers to increase profits. "Focusing on any single factor, such as the point of purchase, the upfront cost of the ink cartridge or printer, the cost per page, or the number of milliliters of ink in a given ink cartridge, is not an accurate way to measure the cost of printing," HP said in a statement. It said consumers should pay attention to the cost of printing per page. It claims that on its Officejet Pro models, the cost of ink per page has remained at the same level since 2009.

At the same time, Epson believes that due to technological advancements, print heads are more efficient than they were 10 years ago. The company said in a statement: "They can make more pages with the same amount of ink."

Among the leading manufacturers, Canon is the weakest in reducing ink, but sales are still declining. For example, its most recent PGI-525BK inkjet cartridge contains 19 ml of ink, while its BCI-3BK released in 2005 is 26 ml. The company also introduced standard and XL ink cartridges.

Critics admit that technology has improved and that modern print heads are more efficient. "But these improvements do not prove that the amount of ink in the cartridge has been reduced by a factor of five," Brooks said. “The cost of printer ink is the lowest ever, a liter of only a few euros. Many ink cartridges cost less than 50 pence to manufacture. The price increase is huge. Compared with ten years ago, today’s consumers pay proportionally higher fees. It is more used for ink cartridges with very little ink."

There is a fierce battle between the manufacturers (HP, Epson, and Canon) and the "remanufacturers" represented by Brooks. They refill the ink cartridges at a discount. While counterfeit ink cartridges from China flooded into the UK, remanufacturers accounted for one-third of UK sales.

In addition, fierce competition from new entrants such as Kodak has eroded their bottom line. Kodak entered the market in the mid-2000s, offering cheap plastic printers and even cheaper ink cartridges. (Kodak said last year that it would withdraw from the inkjet market.)

"The market share of the three giants is declining year by year," Brooks said. "They have to do some drastic things."

The response is to sell cheaper printers and recover the money for low ink cartridges. Consumers must replace ink cartridges more frequently. Ten years ago, the average cost of home printers was as high as 150 pounds, but today their retail prices are as low as 30 pounds.

Many new printers come with "start-up" cartridges that contain a small amount of ink, so owners must purchase new cartridges almost immediately. Others have embedded technology to stop cheap refills. "The logic is simple," Stead said. "Once consumers buy an HP printer, no matter how much it costs, they must buy HP ink cartridges."