diff --git a/backend/hp5400.h b/backend/hp5400.h
index 78244e0f1..bf61a2360 100644
--- a/backend/hp5400.h
+++ b/backend/hp5400.h
@@ -112,7 +112,7 @@ THWParams;
 
 /* The scanner needs a Base DPI off which all it's calibration and
  * offset/size parameters are based.  For the time being this is the same as
- * the iDpi but maybe we want it seperate. This is because while this field
+ * the iDpi but maybe we want it separate. This is because while this field
  * would have limited values (300,600,1200,2400) the x/y dpi can vary. The
  * windows interface seems to allow 200dpi (though I've never tried it). We
  * need to decide how these values are related to the HW coordinates. */
diff --git a/backend/hp5400_internal.c b/backend/hp5400_internal.c
index 1d81358c1..350c806a7 100644
--- a/backend/hp5400_internal.c
+++ b/backend/hp5400_internal.c
@@ -385,7 +385,7 @@ SetCalibration (int iHandle, int numPixels, unsigned int *low_vals[3],
       i = j / numLoop;
 
       /* This is obviously not quite right. The values on
-       * the right are approximatly what windows sends */
+       * the right are approximately what windows sends */
       k = (high_vals[0][i] > 0x4000) ? 1000000000 / high_vals[0][i] : 0;	/* 0x6700 */
       pixel->highr[0] = k;
       pixel->highr[1] = k >> 8;
@@ -781,7 +781,7 @@ DoAverageScan (int iHandle, struct ScanRequest *req, int code,
   HWParams.iXferHandle = iHandle;
 
   if (InitScan2 (SCAN_TYPE_CALIBRATION, req, &HWParams, &res, 0, code) != 0)
-    return -1;			/* No colour offseting, we want raw */
+    return -1;			/* No colour offsetting, we want raw */
 
   length = htonl (res.xsize) / 6;
 
@@ -1204,7 +1204,7 @@ InitScan2 (enum ScanType scantype, struct ScanRequest *req,
 
   /* Protect scanner from damage. This stops stpuid errors.  It basically
    * limits you to the scanner glass. Stuff like calibrations which need
-   * more access do it safely by fiddling other paramters. Note you can
+   * more access do it safely by fiddling other parameters. Note you can
    * still break things by fiddling the ScanOffset, but that is not yet
    * under user control */
 
diff --git a/backend/hp5400_internal.h b/backend/hp5400_internal.h
index aa40da02b..42141e9ca 100644
--- a/backend/hp5400_internal.h
+++ b/backend/hp5400_internal.h
@@ -112,7 +112,7 @@ struct ScanRequest
    */
   uint8_t zero;			/* Seems to always be zero */
   uint16_t gamma[3];		/* Set to 100 in network order. Gamma? */
-  uint16_t pad[3];		/* Zero padding ot 32 bytes??? */
+  uint16_t pad[3];		/* Zero padding to 32 bytes??? */
 }
 PACKED;
 
@@ -154,7 +154,7 @@ PACKED;
  * what we wish change and SET it back otherwise goodness knows what evil
  * we will unleash.
  *
- * Note that for setting, different values in the buffer seem to apply betwen the copy count
+ * Note that for setting, different values in the buffer seem to apply between the copy count
  * and the colour/BW switch setting. I don't know what that means at the moment.
  *
  * I'm calling it PanelInfo because I can't think of anything better.