The Autopsied Printer

In this instructable we will disassemble an HP printer and scanner. The funktion of this instructable is to give you an idea of which components the machine consist of, how they work, how they are made, what they are made of and to what extend they can be recycled.

At last we will go trough how to make the disassembly model.

First we removed the paper entering and exiting compartment, these parts clicked off. The outer shell is mainly made of two parts. The top and the bottom part of the printer. They where disassembled by removing the 4 screws placed in each corner of the outer shell.

The whole outer shell is made of HIPS, HIPS is often shaped by Injection molding and vacuum forming. The outer shell is most likely injection molded due to the complexity of the structure.

The process of scanning an image is in itself feral simple and can be easily understood through image nr. 3. The scanned image is produced with an image sensor. The image censor consists of a long metal string (image 4, object 5) that receives reflected light from the scanned object. The light reflected by the object origins from an LED. The light from the LED is spread out by the light conductor (image 4, object 2). The data is then registered while the censor moves across the transparrent plexiglass surface and scans the image one row of pixels at a time, boom there you have it!

The light conductor is made by 2 parts. First, an LED that sends light trough a glass plate, the glass is engraved like seen on image 5 and 6 (with and without light) the size of the engraving grows with the distance of the LED. The effect of the growing engraving is: The longer the distance is from the LED, the bigger the amount of light being reflected. This means that the engraving compensates for the intensity decrease and thus is the light spread equally, despite an odd lightsource. The light conductor, the LED and the image sensor are all mounted in a plastic case made of ABS. If your scanner is broken you will most likely not be able to repair it yourself. All parts are glued together and in order to get them apart we had to break the conduction glass and cut the glue off. Besides not being able to repair it is also almost impossible to recycle responsibly. This is why buying HP printers is a good idea recycle wise. HP has a recycle center for their printers to compensate for the environment mess they are making.

The paper is transported through the machine with several low voltage steppermotors geared up to a steel rod. One of the central transportation rods is seen above. The rod is placed in the center of the printer. The rod is coated in rubber acceptable to increase friction for smooth transportation.

This part was removed by unscrewing 2 screws and clicking the part out of the printer. The parts on the rod is mounted with screw and glue but they come off fairly easy. This part of the printer is easy to recycle once you have taken it apart. It consists of ABS, rubber, aluminium and a stepper motor. Steel, and ABS is easy to recycle. It is simply melted and then you can recast it. The rubber can also be recycled through different methods. And at last, the stepper motor which you should just save, cause.. you know, there will always be someting you can use that for.

A quick overview would sound a little like this:

1. Under instructions from your computer, an electronic circuit in the printer figures out which nozzles have to be fired to print a particular character at a certain point on the page. Hundreds of nozzles are involved in making a single character and each one is only about a tenth as thick as a human hair!

2. The circuit activates each of the nozzles by passing an electric current through a small resistor inside it.

3. When electricity flows through the resistor, it heats up.

4. Heat from the resistor boils the ink inside the nozzle immediately next to it.

5. As the ink boils, it forms into a bubble of ink vapor. The bubble expands enormously and bursts.

6. When the bubble pops, it squirts the ink it contained onto the page in a precisely formed dot.

7. The collapsing bubble creates a partial vacuum in the nozzle that draws in more ink from the ink tank, ready for printing the next dot.

8. Meanwhile the entire print head (light orange) is moving to the side ready to print the next character. The walkthrough comes from explainthatstuff.com, look it up for more information on different types of printers.

- Universal glue

- Stanly knife

- Torx screwdriver

- Steal wire

- Square pice of cardboard ( 2 x 2 m)

- A lot of paper (for the ink left in the machine)

- Battery (3,7 v)

- Straws

- Wooden board

The disassembly model - Setup, cut halfway through the cardboard and fold it like the paper model seen in picture one.

Place the shell of the machine on straws supported with steal wire in the center of the cardboard.

Then make 4 holes in the cap of the scanner and in the cardboard's walls, take the wire through the cardboard so the cap of the scanner is floating above the shell.

Divide the inner printer into sections as in: ink department, printer internals, image censor, paper transportation and scanner internals.

Take all the center parts of the machine and place them in front of the printer, in the order it is taken out, the further in, the further away from the shell. Most of it is easy to remove.

Mount all the electronics and gears from the scanner on one side of the wall, to give an overview of what the scanner consists of, all the pieces are glued on and heavy or large items are placed with steal wire.

Mount all the components that handle the ink on the opposite wall of the scanner department.

The back of the printer contains an entrance transportation rod for the paper. The rubber and springs are taken off the rod. This part is taken apart and placed next to the printer, for better overview.

To divide the printer into sections we made labels made out of MDF and placed them with glue in their related sections. The text is engraved in the labels and in the glass board of the printer, by using a laser cutter. The files can be downloaded below.

The stepper motor driving the transportation rod is connected to a battery and a button in series. The button is installed in a box to hide the 3,7 V battery, the file for the box can also be downloaded+ below.

In the end we wrote "PRINT" with the screws in the right corner using a glue gun pistol.