How to use PDF to PNG format for OCR without saving each page as PNG?

Question

I am using OCR to scan invoices, and I have a large collection of PDFs. The code I am using to convert the PDF to PNG is the following:

import fitz
file_path = "my_file.pdf"
dpi = 500 
zoom = dpi / 72  # zoom factor, standard: 72 dpi
magnify = fitz.Matrix(zoom, zoom) 
doc = fitz.open(f'my_file.pdf') 
for page in doc:
    pix = page.get_pixmap(matrix=magnify) 
    pix.save(f"page-{page.number}.png")

I then take each PNG and perform OCR on it.

Now I don't want to save the new png file each time and accumulate hundreds of stored PNG's, rather I just want the OCR output saved. Is there a way to keep the format of PNG just within the code and NOT have to save each page of the PDF as a PNG in my folder?