Dell 720 Color Inkjet Printer

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Bucknell Mechanical Design Home


Dell 720 Inkjet Printer

Dell Printer.jpg


The dell printer is designed to print ink onto papers. This is a cheaper version of a printer and is often given out by dell free with the purchase of a computer bundle.

How The Printer Works

The Primary function of the printer is to spray the ink onto the paper in distinguishable patterns.

This is accomplished by:

1. Feeding in the paper.

2. Moving the ink jets laterally.

3. Spraying the ink onto the paper.

4. Feeding the paper out of the system.


The table belows Contains the Components in the Dell 720 Inkjet Printer:

Table 1: Dell 720 Inkjet Component List
Part # Part Name Category Function Material Picture
1 Casing Structural Component Protection Plastic Buckcase.jpg
2 Roller #1 Output / Transmission Brings Paper from feeder into tray Plastic / Rubber coating Buck1226.JPG
3 Motor #1 (Right Motor) Input Power Feed system for gear train Metal motor, plastic components Buck1227.JPG
4 Roller #2(Feed Out) Output / Transmission Feed Paper through and out of printer Plastic Buck1229.JPG
5 Sensor Motion Conversion Element When tripped switches direction of motor one to engage roller two instead of the roller one system Plastic Buck1231.JPG
6 Motor #2 Input Power the drive train for ink Jets Metal / Plastic Buck1234.JPG
7 Drive Train Transmission Brings ink jet laterally across the machine Metal / Plastic / Rubber Buck1236.JPG
8 Docking Station Structural / Motion Conversion Pops up and covers ink jets when cartridge is in docking position Rubber / Plastic / Metal Springs Buck1237.JPG

Lets Head to the Computer

After looking at the components that make up a printer we modeled two of the components to healp us quantitativly verify how the printer works.

The Slider Mechanism

One motion of the printer that can be modeled and explored is the action of the inkjet acriss the paper. This is shown below modeled with the inkjet, the rod it slides along, the motor and the belt that controlls the motion.

Figure 1: Isometric View
Figure 2: Top View
Figure 3: Front View

The Adams Analysis

To analyze the data we can model this system in adams. The simulation to be run will use a step function to define the velocity of the printer head across the paper. This velocity was calculated from the knowledge of how many pages per minute the printer prints and turns out to be 29 inches per second. With this data we can run a simplified simulation of the printers motion.

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Animated Printer Carriage

The Results

From the result of the simulation we have procured graphs of velocity and acceleration as the printer makes one pass of its motion, starting in the center and ending the same.

Figure 4: Velocity of Printer Head
Figure 5: Acceleration of Printer Head

From looking at the acceleration graph we notice that the highest value is around 425 inches per second squared. Using F = m a the largest force acting on the inkjet as found in our simulation is 1.025 N. This value is also highest force acting on the motor and belt of the printer.


To improve the design a possible fix could be to make a stronger belt attatching to the inkjet head to make the printer able to run at higher speeds. This would improve the printer because the printer would be able to pump out printing more pages per minute. Also if you had some sort of lubrication mechanism attatched to the support rod this would make the inkjet able to move quicker across the paper.

The Docking Station

Another mechanism that can be modeled and explored is the cartridge docking station. The docking station is made of an assembly of three parts.

Rotating Piece
Upper Base Piece
Lower Base Piece
Docking Station Assembly

The Beam Analysis

The vertical tab of the assembly gets contacted by the printer cartridges at the end of each printing session when the cartridges are docked. This tab must be able to withstand the force of the cartridges without failing. The tab was modeled as a simple beam of rectangular cross-seciton and bending moment analysis was done to find the maximum withstandable force. (Some assumptions were: the width of the cross-section is 3 times the thickness, the yield strength is 10,000psi)

The Results

The results of the beam analysis showed that the maximum allowable force that the tab could withstand was 12.8lb. The load that the tab will actually be required to withstand is estimated to be .25lb. This gives us a factor of safety of 51.2. This tells us that the tab will never come close to yielding or fracturing. The minimum thickness of the tab was calculated to be .0215in (still assuming the width is three times the thickness). That would be a very small tab, and would actually be harder to manufacture than a larger tab.


The docking station for this printer model seems to be very efficient. This docking process requires no actuator to function, and takes up very little space. Therefore, no improvement is needed for this design.