Product Dissection: Gate 2

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Figure 1: The remnants of our HP Officejet 7310, "Inky."


Project Management: Preliminary Project Review

Cause for Corrective Action

The work and management plans that we put forth in gate one were put to the test in gate two. On the management side of things, our group couldn’t have been stronger. Every Monday, Wednesday, and Friday we met, and at each meeting we were productive and efficient in our tasks. When it came time to work each member stuck to their role, completing what was needed of them in accordance to their particular skill set. This management plan worked so well in large part due to our frequent meetings. By meeting often, we ensured that our group never fell behind, thereby making us far better prepared than had we met only once a week. The frequent meetings also highlighted each member’s certain talents, and by working in close contact with one another we established a strong bond and friendship that should not be underrated. Our group’s good chemistry led to a decreased chance at there being a conflict between the members, as well as creating a far more enjoyable work environment which led to increased and improved production.

Our work plan in the beginning was to start at the top and work our way down. We didn’t know what was inside the HP Officejet 7310, and therefore had no idea what to expect. As a result we did some research and found a list of steps that seemed helpful to dismantling our product. Once we began the actual disassembly process however, these steps soon became useless. The outline was far too vague and left out a great number of steps in between. Despite this minor setback, the very simple work plan of, “playing it by ear,” worked very well for us. In a product like the Officejet, many of the subsystems and components are layered one on top of the other. Once we realized this it was a relatively minor task to locate and remove the upper layers before exposing the lower.

One of the most imposing challenges we faced was the organization of the Officejet’s many parts. In order to do this, we divided the printer up into three main sections; the fax, the scanner, and the printer. To these we gave the numbers 1, 2 and 3. For each subsystem that came off of one of these mother functions, we assigned a decimal number, (For example, a system that came off of the fax may be labeled 1.2) and for each system or component to come off of that subfunction we assigned a further corresponding decimal (e.g. 1.2.1). By labeling each part with these numbers we now know exactly which system it belongs to.

Our primary method to avoid or overcome future challenges will be to have good time management. Last minute work is never the best it could be. By leaving ourselves some room to spare, our future work will be more thorough, complete, and contain a minimum amount of mistakes.

Product Archaeology: Product Dissection

Ease of Disassembly

In order to assign a level of difficulty to each step of our dissection, we created this scale.

Table 1: Difficulty Scale
Difficulty # Description
  • These simple tasks require very little force. It is easy to see what to do for these kinds of steps and usually only two parts are involved in the process.
  • For these kinds of steps it may be necessary to unscrew components each other, requiring the use of a screwdriver. These steps may also require some tricky adjustments of the parts to get them into the proper location before removal.
  • More than two parts are usually involved in these steps. Often there may be multiple parts held in place by one screw. Some parts must be moved, sometimes with force, out of the way before other parts can be taken off. A step requiring a greater deal of force is also considered a 3.
  • These complex tasks don’t usually require a great deal of force, but take place in a tight environment. There are often many parts involved, and it isn’t all that easy to see what each part does and where it is attached to the product. For these tasks the use of multiple people may be necessary.
  • These steps not only take place in a small environment, but require a great deal of force as well. Multiple people are necessary for these tasks, as there will be a number of stages that must be completed simultaneously. Visibility will be low, making it very difficult to see what is being done.

Dissection Process

During our dissection process the biggest problem we faced was that we had no clue in what order to take apart our product. The difficulty of “flying blind” shows up in our step-by-step procedure, as we made a couple jumps between parts and steps on the path to our end goal. In overcoming this lack of foresight our organization was a key component. By documenting the vast array of parts we uncovered, we never lost track of what we did or where we were. Only through that discipline could we disassemble our product without confusion.

Another challenge we faced was figuring out in which order to remove the parts. We had a general idea, starting at the top and working down, but often as we tried to take off one part we realized another piece was in its way. There was no real solution to this problem. When this problem was encountered we simply left that specific part be until other parts were cleared to make room.

Table 2: Dissection Process
Step # Parts Procedure Tools Difficulty Image
1 Outer casing Use screwdriver as a lever to simply pry the grey casing piece off of the side of the printer. The removal of this part is necessary for access to other components that may need repair, so this part is intended to be disassembled.
  • Screwdriver (Note: All screws are hex)
  • Hands
1 Inkyproc1.JPG
2 Fax head / scan door Remove screws to disconnect from the rest of the printer, then pop off fax head/scan door. This part is intended to be disassembled as it encompasses components that may require maintenance.
  • Screwdriver
  • Hands
2 Inkyproc2.JPG
3 Fax assembly Similar to Step 1, use screwdriver for leverage to pry off the other grey casing piece from the assembly. Remove two screws from the underside of the scan door to detach the fax cover from fax mechanism. Remove any visible screws to detach the fax mechanism from the scan door. See Video
  • Hands
  • Screwdriver
3 Inkyproc3.JPG
4 Scan top Gently and securely peel the white sheet off the underside of the scan door. Grip the grey casing piece on the end of the scan door and snap off to detach. The sheet is unintended to be disassembled as it serves no purpose for repair and is essentially ripped off with no intention of everyday reassembly.
  • Hands
1 Inkyproc4.JPG
5 Fax mechanism Remove one screw and flat white rod from the fax assembly, then snap off the clear fax tray to separate from the fax mechanism. The separation of these components is intended, because it allows for more convenient access to the fax mechanism and its subcomponents. See Video
  • Screwdriver
  • Hands
2 Inkyproc5.JPG
6 Fax tray Remove one screw from the center of the tray to detach another smaller tray. Use screwdriver to pry off the 2 black-toothed components. After disassembly, the two translucent grey shutters will consequently be removed. This part is unintended to be disassembled as it does not require repair or contain any other vital components.
  • Screwdriver
3 Inkyproc6.JPG
7 Fax mechanism Begin by removing one screw from the grey casing of the gearbox to separate the cylindrical component from the fax mechanism. Grip the two wires and pull apart from the small circuit board. Remove a total of three screws to detatch the gear plate and uncover the gear train. This part is intended to be disassembled as it houses a set of gears which may need repair. See Video
  • Hands
  • Screwdriver
2 Inkyproc7.JPG
8 Gear plate Removed in the previous step. The gears on the gear plate can be taken off by pulling them. This part may have need of repair and is intended to be disassembled.
  • Hands
1 Inkyproc8.JPG
9 Fax mechanism Slide off the gear cluster in the corner of the fax mechanism. Remove all visible screws and their corresponding components and parts. These gears and parts are meant to be removed for repair purposes.
  • Hands
  • Screwdriver
2 Inkyproc10.JPG
10 Gear box Continue to remove gears by sliding them off of their shafts. These are intended to be removed for repair purposes.
  • Hands
1 Inkyproc12.JPG
11 Fax roller With the plate removed from the fax mechanism, the shaft of the fax roller can be pushed out and removed. This is a part with many smaller pieces that may be in need of repair and is intended to be disassembled.
  • Hands
1 Inkyproc9.JPG
12 Fax roller To separate the fax roller from itself push down on the green button. This part is intended to be disassembled. See Video
  • Hands
1 Inkyproc11.JPG
13 Fax mechanism Gently pop off the paper guides. These parts are not made to be disassembled as they serve no purpose in repair.
  • Hands
1 Inkyproc13.JPG
14 Scanner Set the fax subsystem aside and bring forward the scanner/printer.
  • Hands
1 Inkyproc15.JPG
15 Printer back Remove the screws holding on the back of the printer, this will allow for easy removal of the piece. This is a part that is intended to be removed in order to access the many parts within that may need repair or in the case of a paper jam.
  • Screwdriver
2 Inkyproc14.JPG
16 Scanner glass Remove the screws holding the plastic frame encasing the scanner glass. Gently lift the plastic frame off of the scanner body being careful not to let the glass slide out. This is intended to be removed in case of a scratch or break in the glass.
  • Screwdriver
2 Inkyproc16.JPG
17 Control interface Pop off outer casing of the control interface, exposing the plate on which the buttons are attached. This will require a minimal amount of force as it is intended to be removed in order to label some of the buttons. Then pop off the plate with the buttons using slightly more force. Any wires attached to the plate will need to be unplugged. This part is intended to be disassembled in case a button needs to be replaced.
  • Hands
1 Inkyproc17.JPG
18 Scan head Remove the screws securing the scan head to the motor and shaft, and pull out the information ribbon. This part is intended to be removed for access to the motor or replacement of the scan head itself.
  • Hands
  • Screwdriver
1 Inkyproc18.JPG
19 Scan cavity Once the scan head is removed, the cavity is exposed, allowing for the removal of the shaft, motor, and other parts that may need to be accessed.
  • Screwdriver
1 Inkyproc19.JPG
20 Scanner/sides Remove the sides of the printer by prying from the back edge until they pop off. Once this is done the scanner can be removed by applying some force to push it out of its moorings. The sides are intended to be disassembled, allowing easy access to the circuit board. The scanner however is not meant to be detached from the printer, as it serves no purpose for repair. See Video
  • Hands
  • Screwdriver
4 Inkyproc20.JPG
21 Scan belt Remove any screws from the scanner shaft and lift the belt, shaft, and motor off. This part is intended to be disassembled, it isn’t that difficult to reach and has parts they may need repair.
  • Hands
  • Screwdriver
2 Inkyproc21.JPG
22 Cover Remove any screws holding the cover to the structural skeleton and snap it off from any plastic joints. This part covers up many components that may need repair and is intended to be disassembled.
  • Hands
  • Screwdriver
2 Inkyproc22.JPG
23 Printer control board After removing the control board supports, the control board can be easily detached by unscrewing the four screws holding it in place. The control board is intended to be disassembled for repair purposes, and is not buried by many components.
  • Screwdriver
2 Inkyproc23.JPG
24 Motor #1 Unscrew the screws that are holding the motor in place. Once the plastic cover is removed the motor is easy to access and in case of a failure is intended to be disassembled and replaced.
  • Screwdriver
2 Inkyproc24.JPG
25 Motor #2 After removing Motor #1, gently pull off the belt guiders, and then unscrew the screws holding the second motor in place. Once the plastic cover is removed the motor is easy to access and in case of a failure is intended to be disassembled and replaced.
  • Screwdriver
2 Inkyproc25.JPG
26 Structural skeleton Continue to take apart and loosen small parts of the skeleton so they won't get in the way. Some of these may just fall off as other parts are removed. The structural skeleton is not intended for disassembly, as it requires no maintenance and has no purpose to be taken apart.
  • Hands
  • Screwdriver
1-2 Inkyproc26.JPG
27 Encoder strip and scanner belt Both the encoder strip and scanner belt can be easily detached by plucking them off of their moorings. The belt and strip are easily accessible and they are intended to be replaceable for repair purposes.
  • Hands
1 Inkyproc27.JPG
28 Carrier rod Remove the screws on the left and right of the rod and lift it off with the ink cartridge carrier attached. While the rod itself will not need replacement, it is intended to be disassembled in order to gain access to the ink cartridge carrier.
  • Screwdriver
2 Inkyproc28.JPG
29 Ink cartridge carrier Slide the cartridge carrier off of the carrier rod. This is a part with a good deal of human interaction, and therefore it is intended to be disassembled in case it breaks.
  • Hands
1 Inkyproc29.JPG
30 Exit roller support Remove the screws on the left and right of the support and then manually detach it from the roller. This part is not intended to be disassembled, as it is unlikely to break and not covering up many components.
  • Screwdriver
2 Inkyproc30.JPG
31 Compression springs Push on a spring to unlatch it from its hooks on both the structural frame and pressure rollers. These springs are unintended to be disassembled. The rollers they attach to are very unlikely to need repair.
  • Hands
1 Inkyproc31.JPG
32 Pressure rollers Once the springs are removed from the hooks, lift up on the edge of the roller and slide the hook out from underneath the structural support. These four rollers are connected, and caution must be used in order not to break their joints. These parts are unintended to be disassembled; they are unlikely to need repair.
  • Hands
2 Inkyproc32.JPG
33 Structural support With the pressure rollers out of the way, remove any wires attached to this support. Then remove any screws. This part is unintended to be disassembled, as it is structural and will not need repair.
  • Hands
  • Screwdriver
2 Inkyproc33.JPG
34 Paper guide Remove screws holding the paper guide in place. This part is not intended to be disassembled as its removal serves no purpose in repair.
  • Screwdriver
2 Inkyproc34.JPG
35 Reservoir With all other parts out of the way, remove any screws holding the reservoir in place and take it off of the base. This part is intended to be disassembled as it houses a set of gears and a circuit board which may need repair. It is also placed on the outer rim of the printer for easier access.
  • Hands
  • Screwdriver
2 Inkyproc35.JPG
36 Structural support With the paper guides out of the way, remove screws holding grey structural support in place and unhook the tabs connecting it to the other supports. This part is unintended to be disassembled as it is structural and needs no repair.
  • Screwdriver
2 Inkyproc36.JPG
37 Gear box By rotating the white locks holding the shafts in place, both shafts and the gear box can be removed. While the gear box is necessary to access, it is unnecessary to remove from the printer and therefore unintended to be disassembled.
  • Pliers
2 Inkyproc37.JPG
38 Gear box cover Snap the cover off of the gear box. This part is intended to be disassembled in order to gain access to the gear box.
  • Hands
1 Inkyproc38.JPG
39 Base cover Remove the screw holding the base cover in place. Doing this allows the base to be removed, which serves no repair or user purpose and is therefore unintended to be disassembled.
  • Screwdriver
2 Inkyproc39.JPG
40 Base and print tray Unscrew tray from base and lift off. This part is intended to be disassembled by the user in case of a lack of space. Slide the base off from the frame. This part is unintended to be removed.
  • Hands
  • Screwdriver
2 Inkyproc40.JPG
41 Rear guide Remove screw holding guide in place to remove from frame. This part is unintended to be disassembled as it cannot be reached without taking apart the whole printer.
  • Hands
  • Screwdriver
2 Inkyproc41.JPG
42 Frame Remove any wires or stray parts from the frame, and the HP Officejet 7310 is completely disassembled.
  • Hands
1 Inkyproc42.JPG


The systems shown below are the numerous functions that make up the HP Officejet 7310. At each new level the functions and systems become less complex until there is nothing left but the most basic components. By connecting all these subsystems through the various physical, signal, mass, and energy flows, it allows the “all-in-one” printing process to be fully automated after the initial human interaction. Without these connections we would simply have a printer, a scanner and a fax machine, and it is only by joining these subsystems together that a new and unique product is acquired. Physically, the subsystems are connected mainly through the use of screws and plastic snaps. Two pieces may snap into each other, and then be fastened by the screw. Some signals that are sent between the subsystems include where to move the carriage and when to spray the ink. These signals come from the computer initially, but are transformed by use for the printer in the buffer. Mass flows consist of paper and ink. Paper flows through the rollers, while ink is stored in the cartridge and leave via the nozzle. Human energy is required to start the printer going, but it is electrical energy that powers all the movable parts within the printer.

Figure 2 - Overall Product Function

This level shows the initial input and final output flows of the product.

Overall Product Function

Figure 3 - First Level Subfunctions

On the first level the three primary functions of the product are broken down. The signal flows that connect these subfunctions allow them to communicate with each other. The scan or fax first process the information, and then send it to the printer to be put on paper.

First Level Subfunctions

Figure 4 - Second Level Subfunctions

The second level of subfunctions still primarily consists of signal flows. These flows serve the same purpose as they did in the first level, allowing the three primary functions to communicate. There are also new signal flows however within the three primary functions which transmit information between their subfunctions. The energy flow of electricity flows throughout the product, giving power to the functions.

Second Level Subfunctions

Figure 5 - Third Level Subfunctions

On the third level, signal flows still pass through the subfunctions, sharing information within the product. Energy flows of electricity power movable parts, lights, circuit boards, and the display screen. The material flow of paper travels through the fax to the encoder so that the information on the paper can be converted into digital information. Paper is fed through the print rollers and ink through the spray head so that ink can be placed on the paper.

Third Level Subfunctions

Figure 6 - Fourth Level Components

Down here on the component level of the product the flows running between the parts are much more distinct. Looking at the fax encoder for example, a signal is now only sent to one part of that subfunction, the motor. From there mechanical energy is transferred to the belt so the material flow of paper may pass through the encoder. All the parts are connected in one way or another to each other through material, signal, mass, or energy flows. Without these flows the parts would not be able to coordinate and function with each other.

Fourth Level Subfunctions

Connection Implementation and Arrangement

The ability to fax, scan, and print require very accurate and precise movements. This fine level of performance calls for very low tolerances on many of the moving parts and the physical connections that join them together. All these functions have to be done in a very small space as well, making the flexible wires and electrical signals running through them crucial to coordinating movement.

Just by looking at the exterior of the all-in-one printer the display of ease of use is evident. The fax machine is at the top, scanner in the middle, printer at the bottom, and the easily seen and operated control panel is right in the front. Having all of these subsystems in sections simplifies the user’s objective, so they won’t have to search around the printer to complete a task. This also addresses the societal concern of having three separate machines on the consumer's desktop, which can be visually unappealing and also take away space to work. Having an all-in-one machine where the subsystems are interconnected can be aesthetically beneficial as well as economical. From an economic standpoint, the purchase of three separate office machines will most likely outweigh the purchase of one all-in-one printer. Also, the machine is compact, combining three separate subsystems into one coherent apparatus. This leaves minimal excess space within the printer which leads to decreased material use and lower cost. This cutback on material can also prove to be environmentally friendly. With an all-in-one appliance that utilizes a generally uniform material, the parts are more interchangeable and can be reused or recycled, thus reducing material waste. The economic, environmental, and societal concerns are all correlated and influence the connection of the subsystems simultaneously.

The subsystems involved in the product are arranged in an ideal manner that provides easier access to components that may require repair. The procedure column in Table 2 elaborates on some of these instances. Also, the subsystems are connected in a way that allows for the most efficient transport of the paper throughout the machine.

The overall flow of the faxing, scanning, and printing processes does restrict the subsystems from being arranged in an adjacent manner. The sheets of paper being used must undergo a series of steps in order to export a finished product. Some of these steps can not function simultaneously. For example, the ink does not get applied to the page while the scanning subsystem is performing. The paper is passed from stage to stage. Thus, adjacent alignment would constrain and ultimately prevent the subsystems from coexisting.

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