ribbon – Experimental Engineering

Posted on February 22, 2018 by The Engineer — 1 Comment

Brother PT-E300 Industrial Label Machine Teardown

Here a tape is installed in the printer. This unit can handle tape widths up to 18mm. The pinch rollers are operated by the white lever at the top of the image, which engages with the back cover.

This printer is supplied with a rechargeable battery pack, but AA cells can be used as well. Some of the AA battery terminals can be seen above the battery.

Pretty standard fare for a 2-cell lithium pack. The charging circuitry doesn’t appear to charge it to full voltage though, most likely to get the most life from the pack.

With the cartridge removed, the printer components can be seen. As these cartridges have in effect two rolls, one fro the ribbon & one for the actual label, there are two drive points.

The thermal print head is hidden on the other side of the steel heatsink, while the pinch rollers are on the top right. The plastic piece above the print head heatsink has a matrix of switches that engage with holes in the top of the label cartridge, this is how the machine knows what size of ribbon is fitted.

Most of the internal space is taken up by the main board, with the microprocessor & it’s program flash ROM top & centre.

The charger input is located on the keyboard PCB just under the mainboard, which is centre negative, as opposed to 99% of other devices using centre positive, the bastards.

The dot-matrix LCD is attached to the mainboard with a short flex cable, and from the few connections, this is probably SPI or I²C.

The printer itself is driven by a simple DC motor, speed is regulated by a pair of photo-interrupters forming an encoder on the second gear in the train.

The back case has the battery connections for both the lithium pack & the AA cells, the lithium pack has a 3rd connection, probably for temperature sensing.

Posted on August 11, 2015 by The Engineer — 3 Comments

Evolis Dualys3 Card Printer Teardown

I recently dug out my other card printer to fit it with a 12v regulator, (it’s 24v at the moment), and figured I’d do a teardown post while I had the thing in bits.

This is a less industrial unit than my Zebra P330i, but unlike the Zebra, it has automatic duplexing, it doesn’t have Ethernet connectivity though.

Unlike domestic printers, which are built down to a price, these machines are very much built up to a spec, and feature some very high quality components.

Here’s the mechanism with the cowling removed. This is the main drive side of the printer, with the main drive stepper at left, ribbon take-up spool motor lower right, and the duplex module stepper motors at far right.

The main drive motor runs the various rollers in the card path through a pair of synchronous belts, shown here.

The stepper itself is a quality ball-bearing Sanyo Denki bipolar motor.

Electrical drive is provided to the stepper with a L6258EX DMOS universal motor driver. This chip can also drive DC motors as well as steppers.

Here is the encoder geared onto the ribbon supply spool. This is used to monitor the speed the ribbon is moving relative to the card.

Here’s a top view through the printer, the blue roller on the left cleans the card as it’s pulled from the feeder, the gold coloured spool to it’s right is the ribbon supply reel. The cooling fan on the right serves to stop the print head overheating during heavy use.

The spool take-up reel is powered by another very high quality motor, a Buhler DC gearmotor. These printers are very heavily over engineered!
This motor drives the spool through an O-Ring belt, before the gear above. This allows the drive to slip in the event the ribbon jams, preventing it from breaking.

The pair of steppers that operate the duplexing unit are driven by a separate board, with a pair of L6219DS bipolar stepper driver ICs. There are also a couple of opto-sensors on this board for the output hopper.

All the mechanisms of the printer are controlled from this main PCB, which handles all logic & power supply functions. Sections on the board are unpopulated, these would be for the Ethernet interface, smart card programming & magstripe programming.

The brains of the operation is this ColdFire MCF5208CVM166 32-bit microprocessor. It features 16KB of RAM, 8KB of cache, DMA controller, 3 UARTs, SPI, 10/100M Ethernet and low power management. This is a fairly powerful processor, running at 166MHz.
It’s paired with an external 128Mbit SDRAM from Samsung, and a Spansion 8Mbit boot sector flash, for firmware storage.

Here the USB interface IC is located. It’s a USBN9604 from Texas Instruments, this interfaces with the main CPU via serial.

Posted on July 14, 2012July 14, 2012 by The Engineer — 1 Comment

MicroVision ShowWX+ HDMI Laser Pico Projector

Here’s the teardown of the projector itself! On the right is the info label from the projector, which covers the flex ribbon to the VGA/composite input board below.

This unit is held together with Allen screws, but is easy to get apart.

Here’s the insides of the projector, with just the top cover removed. The main board can be seen under the shielding can, the Micro HDMI connector is on the left & the MicroUSB connection is on the right. The USB connection is solely for charging the battery & provides no data interface to the unit.

On top of the main board is the shield can covering the PicoP Display Engine driver board, this shield was soldered on so no peek inside unfortunately!

The laser module itself is in the front of the unit, the laser assemblies are closest to the camera, on the left is the Direct Doubled Green module, in the centre is the blue diode, and the red diode on the right. Inside the module itself is an arrangement of mirrors & beamsplitters, used to combine the RGB beams from the lasers into a single beam to create any colour in the spectrum.

Here is the module innards revealed, the laser mounts are at the top of the screen, the green module is still mounted on the base casting.
The three dichroic mirrors in the frame do the beam combining, which is then bounced onto the mirror on the far left of the frame, down below the MEMs. From there a final mirror directs the light onto the MEMs scanning mirror before it leaves through the output window.

A trio of photodiodes caters for beam brightness control & colour control, these are located behind the last dichroic turning mirror in the centre of the picture.