Python打印宏在部分HP激光打印机上静默取消任务的排查求助

阿华AIGC实验室

2026-4-7

大家好，我最近开发了一个Python打印宏，核心功能是把信头粘贴到PDF文档上，再发送到打印机完成打印。这个工具在大部分公司部署后都运行正常，但在部分HP激光打印机上遇到了棘手的问题：打印任务能正常出现在打印机队列中，但很快就会被静默取消，完全没有输出。

已排查的信息：

最初怀疑是老型号打印机内存不足，所以把PDF转位图的DPI从300降到了150，但问题依然存在
测试环境（正常）：HP LaserJet M608
出问题的机型：HP LaserJet 600 M601
同时该宏也会向HP LaserJet 600 M603发送任务（暂时未反馈问题）
程序通过PyInstaller打包为可执行文件分发
使用的依赖库：sys、os、json、win32print、win32ui、win32con、win32gui、fitz、shutil、logging、uuid、PIL、pypdf

关键代码片段：

1. PDF转位图的函数

def convert_to_bitmap(pdf_path, input_name):
    print_queue = []
    # cycle through pages in doc for bitmap conversions
    doc = fitz.open(pdf_path)
    i = 0
    logger.info("Converting PDF file pages to bitmaps")
    for page in doc:
        pixmap = page.get_pixmap(dpi=150)  # convert page to pixel map
        img = Image.frombytes("RGB", [pixmap.width, pixmap.height], pixmap.samples)  # converts pixel map to PIL image
        # creates appropriate path and saves bit map
        uuid4 = uuid.uuid4()
        bitmap_name = f"bitmap({i})-" + str(uuid4) + ".bmp"
        bitmap_path = get_resource_path(f"temp\\{bitmap_name}")
        try:
            img.save(bitmap_path)
        except PermissionError as e:
            logger.error(f"User lacks permission to save bitmap to {bitmap_path}:\n{e} \nExiting program")
            input_path = get_resource_path(os.path.join("temp\\", input_name))
            clean_up(print_queue, input_path, pdf_path)
            sys.exit(1)
        except FileNotFoundError as e:
            logger.error(f"{bitmap_path} is an invalid directory:\n{e} \nExiting program")
            input_path = get_resource_path(os.path.join("temp\\", input_name))
            clean_up(print_queue, input_path, pdf_path)
            sys.exit(1)
        except ValueError as e:
            logger.error(f"Unsupported file format or specifier:\n{e} \nExiting program")
            input_path = get_resource_path(os.path.join("temp\\", input_name))
            clean_up(print_queue, input_path, pdf_path)
            sys.exit(1)
        except OSError as e:
            logger.error(f"OS error encountered:\n{e} \nExiting program")
            input_path = get_resource_path(os.path.join("temp\\", input_name))
            clean_up(print_queue, input_path, pdf_path)
            sys.exit(1)
        except Exception as e:
            logger.error(f"Unexpected error encountered:\n{e} \nExiting program")
            input_path = get_resource_path(os.path.join("temp\\", input_name))
            clean_up(print_queue, input_path, pdf_path)
            sys.exit(1)
        print_queue.append(bitmap_path)  # queues up bitmap for printing
        i = i + 1
        logger.info(f"Page {i + 1}: converted to bitmap")
    logger.info("All PDF file pages converted to bitmaps")
    return print_queue

2. 发送打印任务的函数（关键部分）

def print_pdf(printer, tray, print_queue):
    # cycle through printers to see if passed printer is valid
    printers = win32print.EnumPrinters(win32print.PRINTER_ENUM_LOCAL | win32print.PRINTER_ENUM_CONNECTIONS)
    valid_printer = False
    for p in printers:
        if (p[2] == printer):
            valid_printer = True
            logger.info(f"Printer: {printer} found")
    if (not(valid_printer)):
        # printer not found setting to default
        logger.warning(f"Printer: {printer} not found")
        printer = win32print.GetDefaultPrinter()
        logger.info(f"Printing from default: {printer}")

    # creates handler, device context, memory device context, and starts print job
    printer_handler = win32print.OpenPrinter(printer)
    # acceses printer settings
    devmode = win32print.GetPrinter(printer_handler, 2)["pDevMode"]
    if tray is not None:
        # sets tray if tray >= 0
        if tray >= 0:
            devmode.DefaultSource = tray
            logger.info(f"Tray set to: {tray}")
        else:
            logger.warning(f"Tray set to default: {devmode.DefaultSource}")
    win32print.DocumentProperties(0, printer_handler, printer, devmode, devmode,
                                  win32con.DM_IN_BUFFER | win32con.DM_OUT_BUFFER)

    dc = win32ui.CreateDC()
    dc.CreatePrinterDC(printer)
    memory_dc = dc.CreateCompatibleDC()
    dc.StartDoc("Letterhead on Message")

    # gets page dimensions
    page_width = dc.GetDeviceCaps(win32con.HORZRES)
    page_height = dc.GetDeviceCaps(win32con.VERTRES)

    # cycles bitmaps for each page
    for bm in print_queue:
        dc.StartPage()
        # load bitmap object
        bitmap_handle = win32gui.LoadImage(0, bm, win32con.IMAGE_BITMAP, 0, 0, win32con.LR_LOADFROMFILE)
        bitmap = win32ui.CreateBitmapFromHandle(bitmap_handle)
        old_bitmap = memory_dc.SelectObject(bitmap)
        
        # 原代码此处有截断，以下为现有完整部分
        bitmap_info = bitmap.GetInfo()
        # 后续绘制逻辑（原代码未完全提供）
        # ...