High Resolution Tablet Printer

The Printing International Model PI450-CME High Resolution Tablet Printer for Pharmaceutical Production

 

General Description:

The PI/450-CME production tablet printer is used to print high resolution, single-color images on one side of tablets or capsules. The PI/450-CME can print on a wide range of tablet sizes and shapes, such as on oval, round, and oblong shaped tablets.

The PI 450 is unique in the tablet printing industry.  It utilizes our unique closed ink cup pad printing technology rather than a roll printing technology.  In pad printing the tablet is held stationary by a vacuum while the pad transfers the image to the tablet in a vertical motion.  This, when coupled with the closed ink cup steel doctor blade and high precision image plate, allows the PI450 to produce the highest resolution and clearest print in the industry. Output of over 400,000 tablets per hour is possible.

High quality images on tablets can be important to pharmaceutical manufacturers for the following reasons:

• Protect products from counterfeiting
• Differentiating products from the competition and enhancing brand recognition
• Print machine-readable bar and data-matrix codes
• Clearly marked tablets can reduce patient dosing errors

This outstanding performance is coupled with a CFR 21 part 11 compliant control system and GAMP4 support documentation. In addition to this, the system can be equipped with a visual inspection system that can verify correct printing and reject any out of specification tablets. The printer can also be furnished to with a multi-tablet or a single tablet reject system to work in conjunction with a tablet printer mounted inspection system.

Why Linear Pad Printing Produces More Accurate Images than Rotary Offset Printing:

Our pad printing uses a flexible FDA approved silicone pad, which first picks up the image from the fully inked printing plate; next, the pad is positioned over the tablets, whereupon the pad moves down to transfer the image onto the tablets. The pad then moves up again to repeat the cycle. This linear up-and-down movement of the pad give this unique printing technique its name: linear printing.

Offset printing is based on rotation: the images are transferred onto the tablets by means of a cylindrical rubber roller (mostly made of EPDM). However, this hard rubber cylinder is not flexible enough to conform to the tablets, possibly resulting in damage. Small tablets are especially vulnerable.

On linear pad printing machines, the tablets are secured by a vacuum and do not move when printed. Once printed, the vacuum system switches off and the next group of tablets are positioned for printing.

On rotary printers, the tablets move along underneath the rotating roller as they are being printed. The combination of the rotary and linear movements makes it difficult to perfectly position the tablet for printing.

The following picture clearly illustrates why rotary printers can never obtain the same high quality images that can be obtained with Printing International' s tablet printing installations.

In order to print on a tablet, it is necessary to use more than just a small contact point between the pad and the tablet, but the entire contact surface. The entire image must fit inside this contact surface.

While the tablets are moving with a constant linear speed (V1) the rubber roller is turning with a constant angular speed (V2). This means that points on the rubber roller have a different absolute speeds, depending on their distance from the rotation center. The point closest to the center (V4) has a different speed than a point further from the center (V5). Therefore, slippage between rubber roller and tablet is inevitable.

Our tablet printers do not have this problem because the horizontal speed between the pad and tablets is zero while the image is applied onto the tablet, so there is no slippage when the image (i.e., the entire contact surface mentioned above) is being printed.

This is why our tablet printers reproduce superior quality images.

Principle of Operation:

The printing process begins with the tablet being fed into the brushbox from the hopper via a vibratory channel that is controlled by a level sensor within the brushbox. In the brushbox, the tablets are directed to the voids within the segment plates by 4 rotating brushes. The segment is rotated into position under the print head.  The print head moves backward and picks up the images directly from the etch plate. The head then moves forward to deposit the images onto the tablets, which is held stationary by a vacuum plate. The segment is rotated again, and the ink is dried by either a warm air dryer or IR dryer.  At the next segment rotation, the tablet can be inspected by the Visual Inspection System, or dropped into the output chute.

1. Tablet infeed hopper
2. Vibrating feeder to feed tablets to the brushbox
3. Brushbox, used to fill segment holes with tablets
4. Collector of lost tablets (air knife is blowing them into the collector)
5. Laser to detect upright tablets
6. Printing head
7. Control panel (printer & camera inspection)
8. Electrical cabinet
9. Camera unit
10. IR drier with pyrometer
11. Rejection unit of badly printed tablets
12. Output for good/bad tablets