Printing Issue in Gridview.

Hello

I am using this code for creating Items Price,quantity calculation.

   private void dataGridView1_CellEndEdit(object sender, DataGridViewCellEventArgs e)
        {
            try
            {
                if (e.ColumnIndex == 2 || e.ColumnIndex == 3)
                {
                    // int DISCOUNT;
                    double cell1 = Convert.ToSingle(dataGridView1.CurrentRow.Cells[2].Value);

                    double cell2 = Convert.ToSingle(dataGridView1.CurrentRow.Cells[3].Value);

                    if (cell1.ToString() != "" && cell2.ToString() != "")
                    {
                        //dataGridView1.CurrentRow.Cells
                        dataGridView1.CurrentRow.Cells[4].Value = cell1 * cell2;

                    }
                }
                label1.Visible = true;
                decimal tot = 0;
                for (int i = 0; i <= dataGridView1.RowCount - 1; i++)
                {
                    tot += Convert.ToDecimal(dataGridView1.Rows[i].Cells[4].Value);
                }
                if (tot == 0)
                {
                    //MessageBox.Show("No Records Found");
                }
                txt_netamount.Text = tot.ToString("0.00");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.ToString());
            }
        }

And priting using this code: 

  Bitmap bm = new Bitmap(this.dataGridView1.Width, this.dataGridView1.Height);
            dataGridView1.DrawToBitmap(bm, new Rectangle(0, 0, this.dataGridView1.Width, this.dataGridView1.Height));
            e.Graphics.DrawImage(bm, 50, 650);

after printing am getting this grid in image format so it reduces the print quality.How to print only rows and columns.?