HP DesignJet T2500 User guide - Page 211

Random vertical lines, Wrinkles or folds

Get HP DesignJet T2500 PDF manuals and user guides View all HP DesignJet T2500 manuals
Add to My Manuals
Save this manual to your list of manuals

Page 211 highlights

● A copied or scanned image is very skewed In this chapter the most common defects and failure modes are shown, sorted by relevance and frequency of appearance. A defect is a common image artifact that usually appears when using any CIS scanner. These are due to incorrect settings, product limitations, or easily solvable mistakes. A failure mode is due to malfunctions of some of the scanner components. Some of the corrective actions proposed here require the use of the Scanner Diagnostic Plot, which you can print and scan as indicated in The scanner diagnostic plot on page 219. Please do not use any printed version of this guide to test the scanner, as the resolution of the images included here is insufficient. Use the diagnostic plot when recommended in response to any of the errors described in this chapter. Random vertical lines This is one of the most common issues in sheet-fed scanners. Usually, the vertical streaks are caused by dust particles inside the scanner, or miscalibration of the scanner (in these cases, the problem can be solved). Here are some examples of images suffering from vertical lines or streaks. Please note the black arrow indicating the scanning direction in these examples. Actions 1. Clean the scanner's glass plate and the original to be scanned as described in Clean the scanner's glass plate on page 155. Re-scan your original afterwards. 2. If the streaks remain, recalibrate the scanner as indicated in Calibrate the scanner on page 163. Make sure you clean the maintenance sheet before calibrating the scanner, and check that the maintenance sheet is not damaged (if so, call HP support and ask for a new maintenance sheet). Re-scan your original after the calibration is completed. 3. If the streaks still remain, check the scanner's glass plate visually. If it is damaged (scratched or broken), call HP support. 4. If the streaks remain, there may be dust particles inside the glass plate. Carefully take out the glass plate and clean it as described in Replace the scanner's glass plate on page 158. NOTE: The problem of vertical streaks cannot always be solved, due to the technological limitations of CIS technology. HP offers HD Scanners with CCD technology for higher quality requirements. If the streaks remain after the corrective actions explained above, then no further action can be taken to improve the image quality, except to buy a more expensive CCD scanner. Wrinkles or folds Scanners based on CIS technology have a high optical resolution within their focus plane, at the price of a very limited depth of field. Hence, the images are sharp and detailed when the scanned original is perfectly flat against the glass plate. However, whenever the original contains wrinkles or folds, these defects are clearly visible in the scanned image (as shown in the following example). ENWW Random vertical lines 201

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98
  • 99
  • 100
  • 101
  • 102
  • 103
  • 104
  • 105
  • 106
  • 107
  • 108
  • 109
  • 110
  • 111
  • 112
  • 113
  • 114
  • 115
  • 116
  • 117
  • 118
  • 119
  • 120
  • 121
  • 122
  • 123
  • 124
  • 125
  • 126
  • 127
  • 128
  • 129
  • 130
  • 131
  • 132
  • 133
  • 134
  • 135
  • 136
  • 137
  • 138
  • 139
  • 140
  • 141
  • 142
  • 143
  • 144
  • 145
  • 146
  • 147
  • 148
  • 149
  • 150
  • 151
  • 152
  • 153
  • 154
  • 155
  • 156
  • 157
  • 158
  • 159
  • 160
  • 161
  • 162
  • 163
  • 164
  • 165
  • 166
  • 167
  • 168
  • 169
  • 170
  • 171
  • 172
  • 173
  • 174
  • 175
  • 176
  • 177
  • 178
  • 179
  • 180
  • 181
  • 182
  • 183
  • 184
  • 185
  • 186
  • 187
  • 188
  • 189
  • 190
  • 191
  • 192
  • 193
  • 194
  • 195
  • 196
  • 197
  • 198
  • 199
  • 200
  • 201
  • 202
  • 203
  • 204
  • 205
  • 206
  • 207
  • 208
  • 209
  • 210
  • 211
  • 212
  • 213
  • 214
  • 215
  • 216
  • 217
  • 218
  • 219
  • 220
  • 221
  • 222
  • 223
  • 224
  • 225
  • 226
  • 227
  • 228
  • 229
  • 230
  • 231
  • 232
  • 233
  • 234
  • 235
  • 236
  • 237
  • 238
  • 239
  • 240
  • 241
  • 242
  • 243
  • 244
  • 245
  • 246
  • 247
  • 248
  • 249
  • 250
  • 251
  • 252
  • 253
  • 254
  • 255
  • 256
  • 257
  • 258
  • 259
  • 260
  • 261
  • 262
  • 263
  • 264
  • 265
  • 266
●
A copied or scanned image is very skewed
In this chapter the most common defects and failure modes are shown, sorted by relevance and frequency of
appearance. A defect is a common image artifact that usually appears when using any CIS scanner. These are
due to incorrect settings, product limitations, or easily solvable mistakes. A failure mode is due to
malfunctions of some of the scanner components.
Some of the corrective actions proposed here require the use of the Scanner Diagnostic Plot, which you can
print and scan as indicated in
The scanner diagnostic plot
on page
219
. Please do not use any printed version
of this guide to test the scanner, as the resolution of the images included here is insufficient. Use the
diagnostic plot when recommended in response to any of the errors described in this chapter.
Random vertical lines
This is one of the most common issues in sheet-fed scanners. Usually, the vertical streaks are caused by dust
particles inside the scanner, or miscalibration of the scanner (in these cases, the problem can be solved).
Here are some examples of images suffering from vertical lines or streaks. Please note the black arrow
indicating the scanning direction in these examples.
Actions
1.
Clean the scanner’s glass plate and the original to be scanned as described in
Clean the scanner’s glass
plate
on page
155
. Re-scan your original afterwards.
2.
If the streaks remain, recalibrate the scanner as indicated in
Calibrate the scanner
on page
163
. Make
sure you clean the maintenance sheet before calibrating the scanner, and check that the maintenance
sheet is not damaged (if so, call HP support and ask for a new maintenance sheet). Re-scan your
original after the calibration is completed.
3.
If the streaks still remain, check the scanner’s glass plate visually. If it is damaged (scratched or
broken), call HP support.
4.
If the streaks remain, there may be dust particles inside the glass plate. Carefully take out the glass
plate and clean it as described in
Replace the scanner’s glass plate
on page
158
.
NOTE:
The problem of vertical streaks cannot always be solved, due to the technological limitations of CIS
technology. HP offers HD Scanners with CCD technology for higher quality requirements. If the streaks
remain after the corrective actions explained above, then no further action can be taken to improve the
image quality, except to buy a more expensive CCD scanner.
Wrinkles or folds
Scanners based on CIS technology have a high optical resolution within their focus plane, at the price of a
very limited depth of field. Hence, the images are sharp and detailed when the scanned original is perfectly
flat against the glass plate. However, whenever the original contains wrinkles or folds, these defects are
clearly visible in the scanned image (as shown in the following example).
ENWW
Random vertical lines
201