There is a table dspRunH. It has primary key field - PKey.
There is a child table dspRunD. It has foreign key field - RunH_FK which references dspRunH.PKey.
This child table has an update trigger:

ALTER TRIGGER [CheckOut_Update] ON [dbo].[dspRunD] 
FOR UPDATE
AS
SET NOCOUNT ON
DECLARE @Drv_CD	CHAR(4), @UserOut VARCHAR(25), @UserIn VARCHAR(25), @Invoice_No	CHAR(8)
DECLARE @COut BIT, @CIn	BIT, @FKey INT, @PKey INT
DECLARE @Route_CD CHAR(2), @Run_Time DATETIME, @Trans_Note VARCHAR(100)

SELECT @Invoice_No = Invoice_No, @COut = Checkout, @CIn = Checkin, @FKey = RunH_FK, @PKey = PKey
	FROM Inserted
print 'Trigger - ' + @Invoice_No
SELECT @Drv_CD = Drv_CD, @UserOut = CheckOut_User, @UserIn = CheckIn_User,
		@Route_CD = Route_CD, @Run_Time = Run_Time
	FROM dspRunH WHERE PKey = @FKey
SET @Trans_Note = 'Run ' + @Route_CD + ' ' + CAST(@Run_Time AS CHAR(20))

--Checkout transaction
IF UPDATE(Checkout)
	IF @COut = 1
		EXEC usp_dsp_Invoice_Trans @Invoice_No, 'CHECKOUT', @Drv_CD, @Trans_Note, @UserOut
	ELSE
		EXEC usp_dsp_Invoice_Trans @Invoice_No, 'CHECKOUT_UNDO', @Drv_CD, @Trans_Note, @UserOut

--Checkin transaction	
IF UPDATE(Checkin) AND @CIn = 1
	EXEC usp_dsp_Invoice_Trans @Invoice_No, 'CHECKIN', @Drv_CD, @Trans_Note, @UserIn

The dspRunH record with PKey = 236 has 3 child records in dspRunD table. So when I run this statement:

UPDATE dspRunD SET CheckOut = 1 where RunH_FK = 236

the trigger should fire 3 times, right?
But statement

PRINT 'Trigger - ' + @Invoice_No

prints only once. Why?