mfc-7820n

Brother MFC-J430W WiFi scanner protocol

Reasons

_Brother MFC-J430W has already scanner driver and you can download here_ but that are prebuilt binary (x86/x64) and source code isn't public. This is a problem if you want to use the scanner on ARM architecture, because if you don't have the source code of the driver you can't recompile it. Anyway this should work on every scanner that use brscan4, but I'm not sure.

Scanning protocol

Status codes

When we open a connection with the scanner on port 54921, it respond with his status code:

• +OK 200: Ready to use
• -NG 401: Scanner is busy

Lease

Now we can send a request that specify resolution and color mode, then scanner send to client a offer based on request. I called this part `lease because it recalled me DHCP lease

REQUEST

request := []byte(fmt.Sprintf("\x1bI\nR=%d,%d\nM=%s\n\x80", resolution, resolution, mode))
sendPacket(socket, request)

RESPONSE

300,300,2,209,2480,294,3472

(X,Y)

• response[0] response[1]: Image DPI
• response[3] response[5]: Plane dimensions in mm
• response[4] response[6]: Image resolution in px

COLOR MODES

• GRAY64: gray scale image
• CGRAY: color image
• TEXT: low resolution mode, max output (304x434) [not implemented]

RESOLUTIONS

• 100
• 150
• 300
• 600
• 1200
• 2400

Automatic document feeder

If specified it's possible to disable ADF and scan only one page. Omit this if you want use ADF.

if !adf {
  request = []byte("\x1bD\nADF\n\x80")
  sendPacket(socket, request)
  readPacket(socket)
}

Start scan

Now we are ready to send start scan request:

width = mmToPixels(planeWidth, dpiX)
height = mmToPixels(planeHeight, dpiY)

requestFormat := "\x1bX\nR=%v,%v\nM=%s\nC=%s\nJ=MID\nB=50\nN=50\nA=0,0,%d,%d\n\x80"
request = []byte(fmt.Sprintf(requestFormat, dpiX, dpiY, mode, compression, width, height))

• R = X_DPI, Y_DPI
• M = CGRAY or GRAY64
• C = JPEG or RLENGTH or NONE
• J = MID
• B = 50 (Brightness?)
• N = 50 (Contrast?)
• A = 0,0,WIDTH, HEIGHT

NOTE: WIDTH and HEIGHT are calculated from plane dimensions because width received from response in lease phase is different from width calculated

func mmToPixels(mm int, dpi int) int {
      return int(float64(mm*dpi) / 25.4)
}

Documentation work in progress...

Compile

git clone https://github.com/v0lp3/mfc-j430w.git
go build -o mfc-j430w mfc-j430w/src/*.go

Usage

./mfc-j430w --help

Output:

Usage of ./mfc-j430w:
  -a string
        IP address of the Brother scanner (default "192.168.0.157")
  -c string
        Color mode of the scan (CGRAY, GRAY64) (default "CGRAY")
  -m    Enable scan of all pages from feeder
  -n string
        Name of the output file (default "scan.jpg")
  -r int
        Resolution of the scan (default 300)

To do

• Implement multi page scan for ADF
• Add flag to output compressed image

Credits

Andrea Maugeri

Partially thanks to this