HP Original Toners
Maintenance Kit
Fuser
Spares
HP Thermistor RK2-0359.
A thermistor is an electrical resistor where the resistance-value varies greatly with temperature. All resistances vary somewhat with temperature but in an ordinary resistor this quality is engineered out so far as possible. In a thermistor the variation is deliberately maximised. Thermistors are usually polymer enapsulated material such as sintered metal oxide. In appearance they have two leads joined by a small bead encapsulating the active element. Over a moderate temperature range the response can be nearly linear.
Thermistors are generally considered reliable, particularly if they are used to sense room ambient temperature as this one is.
This part is also known by the Canon number RK2-0359-000 and HP's full code is RK2-0359-000CN.
HP say of this part:
Environment temperature detection thermistor - Detects ambient air temperature to determine length of time for fuser warm up
With this role, the thermistor might conceivably be responsible for 50.2 (fuser warm up) and perhaps 50.3 (high fuser temperature) errors. There is more on fuser faults here .
According to HP Partsurfer the thermistor is used in the LaserJet 4, 4100, 4200, 4240, 4250, 4300, 4345, M4345, M4349 4350, P4014 - an unusually wide range but possible for something with this role.
Some web images suggest you get the metal bracket as well as the thermistor - if you buy a second-hand part that might be true. The new part is a bead thermistor with the lead and plug
On some printers Error 58.xx
and specifically Error 58.2
are specifically associated with the environment sensor. (The same error code has also been used for memory errors so check the service manual). (more here).
Issues which might throw the environment sensor off include:
- An environment that is out of range for the printer - too hot or cold. The operating environment according to the service manual is 7.5° to 32.5°C (45.5° to 90.5°F). Those figures go a bit outside comfortable office conditions but a warehouse on a cold winters day can go below 7 centigrade.
- Bright sunlight heating up the side of the printer can give a loccalised temperature above 32 centigrade.
- Obstruction of the ventilation slots.
- Fan failure allowing localised overheating.
Fixing problems.
- As usual with obscure "didn't heat up properly" errors on laser-printers make sure it is plugged directly into a wall outlet, not a UPS or surge-protector.
- Try powering off and then on again. This error is quite likely to come and go apparently at random.
- Reseat the connector - it could be tarnish or suchlike.
- Replace the thermistor.
- If non of the above work suspect the power supply or DC controller. the environment sensor is plugged into the power supply on route to the DC controller so it is difficult to say which is prime suspect.
Web research doesn't reveal a lot about this part. There are a lot of vendors offering it for sale, both new and as "pulls" (refurbs) from decomissioned machines. Given the low cost of these parts and the potential complexity of diagnosing problems if a second hand item isn't just right we'd suggest buying new manufacturer's originals.
At present we don't know the thermistor's electrical characteristics.
Site printerrepairsupport.com has an article about issues caused by the part.
Copyright G & J Huskinson & MindMachine Associates Ltd 2013, 2015, 2016. Some pictures derived from HP User and Service guides. These technical pages do not constitute an offer for sale; just our knowledge at the time of writing. See the catalog. Sales pages on this Web site use cookies to store user information. We also use Google Analytics to track site usage patterns.