打印条形码不清晰(WPF)

我的应用程序中需要条形码打印模块,但无法弄清楚如何正确打印条形码.看起来它的分辨率太低了.我正在使用Zen Barcode.正如您可以看到每张附照片,顶部条形码是从打印机的软件打印出来的,证明打印机没问题,底部图片是从我的代码中打印出来的:

[WPF]

[C#]

    private void printJob()
    {
        // use printer we need
        SetDefaultPrinter("Brother QL-700");
        //draw barcodes
        BarcodeDraw bc = BarcodeDrawFactory.Code128WithChecksum;

        Bitmap serial_bitmap = (Bitmap)bc.Draw(serial, 20);

        ImageConverter ic = new ImageConverter();

        //generate bitmap
        serial_bcode1.Source = System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(serial_bitmap.GetHbitmap(), IntPtr.Zero, Int32Rect.Empty, BitmapSizeOptions.FromEmptyOptions());

        var dlg = new PrintDialog();

        //print main label
        dlg.PrintTicket.CopyCount = 1; // number of copies
        dlg.PrintTicket.PageOrientation = PageOrientation.Landscape;
        dlg.PrintVisual(_printSerialBcode, "Barcode");

        //change default printer to original one
        SetDefaultPrinter(defaultPrinter);
    }