1sane-sharp(5) SANE Scanner Access Now Easy sane-sharp(5)
2
6 sane-sharp - SANE backend for SHARP scanners
7
9 The sane-sharp library implements a SANE (Scanner Access Now Easy)
10 backend that provides access to Sharp SCSI scanners. This backend
11 should be considered beta-quality software! In the current state it is
12 known to work with JX-610 and JX-250 scanners. It is prepared for usage
13 with the JX-330 series scanners, but we are not able to test it with
14 these devices.
15 For other Sharp scanners, it may or may not work.
17 At present, the following scanners are known to work with this backend.
19 Vendor Product id:
21 ----- -----------
22 Sharp JX-610
23 Sharp JX-250
24 Sharp JX-320
25 Sharp JX-330
26 Sharp JX-350
27 The following scanners are detected by the backend, but not tested:
29 Vendor Product id:
31 ----- -----------
32 Sharp JX-325
33
35 This backend expects device names of the form:
36 special
38 Where special is either the path-name for the special device that cor‐
40 responds to a SCSI scanner. The special device name must be a generic
41 SCSI device or a symlink to such a device. Under Linux, such a device
42 name could be /dev/sga or /dev/sge, for example. See sane-scsi(5) for
43 details.
44
47 --mode Scan Mode. Possible settings are: Lineart (1 bit black & white
48 scans), Gray (8 bit gray scale scans), Lineart Color (bi-level
49 color scans), and Color (8 bit RGB scans). The default value is
50 Color.
51 --halftone-pattern
54 Halftone Pattern. Available only for the JX-330 series scanners.
55 Possible settings: none, Dither Bayer, Dither Spiral, Dither
56 Dispersed and Error Diffusion. The default value is none.
57 --source
60 Paper Source. This option is only available if an automatic doc‐
61 ument feeder or a transparency adapter is installed. Possible
62 settings are: Flatbed, Automatic Document Feeder, and Trans‐
63 parency Adapter. If an ADF or a transparency adapter is
64 installed, using it is the default selection.
65 --custom-gamma
68 Custom Gamma This option determines whether a builtin or a cus‐
69 tom gamma table is used. Possible settings are: yes (enables
70 custom gamma tables) or no (enables a built gamma table).
71 --gamma
74 Gamma. This option is only available if Custom Gamma is set to
75 no. Possible values are: 1.0 or 2.2. The default value is 2.2.
76 (The JX-250 and JX-350 have no built in gamma correction; for
77 these scanners, a gamma table is downloaded to the scanner by
78 the backend.)
79 --gamma-table
82 Gamma Table. Allowed values: 0..255; 256 numbers must be
83 defined. The default values are 0, 1, 2, .. 255 (i.e., gamma ==
84 1). This table is only used for gray scale scans.
85 --red-gamma-table
88 Red Gamma Table. Allowed values: 0..255; 256 numbers must be
89 defined. The default values are 0, 1, 2, .. 255 (i.e., gamma ==
90 1).
91 --green-gamma-table
94 Green Gamma Table. Allowed values: 0..255; 256 numbers must be
95 defined. The default values are 0, 1, 2, .. 255 (i.e., gamma ==
96 1).
97 --blue-gamma-table
100 Blue Gamma Table. Allowed values: 0..255; 256 numbers must be
101 defined. The default values are 0, 1, 2, .. 255 (i.e., gamma ==
102 1).
103 --resolution
106 Selects the resolution of the scanned image. Allowed values:
107 30..600 (JX-330, JX-350 and JX-610) and 30..400 (JX-250). The
108 default value is 150.
109 -l, -t, -x, -y
112 Scan Window. Top-left x position of scan area (-l), top-left y
113 position of scan area (-t), bottom right x position of scan area
114 (-x) and bottom right y position of scan area (-y). The possi‐
115 ble settings depend on the scanner model and, for the JX-250 and
116 the JX-350, also on the usage of the automatic document feeder
117 resp. the transparency adapter. Please refer to the values
118 allowed by xscanimage(1), or xsane(1). With scanimage(1), enter
119 one of the following commands in order to see the allowed param‐
120 eter values for the scan window:
121 scanimage -d sharp --source "Automatic Document Feeder" --help
123 scanimage -d sharp --source Flatbed --help
125 scanimage -d sharp --source "Transparency Adapter" --help
127 --edge emphasis
130 Edge emphasis. This option is not available for the JX-250 and
131 the JX-350. Possible settings: None, Middle, Strong, and Blur.
132 The default value is None.
133 --threshold
136 Sets the threshold for black and white pixels in lineart mode.
137 Possible values are 1..255. The default value is 128. This
138 option is only available in scan mode lineart.
139 --threshold-red
142 Sets the threshold for the red component of a pixel in in lin‐
143 eart color scan mode. Possible values are 1..255. The default
144 value is 128. This option is only available in scan mode color
145 lineart.
146 --threshold-green
149 Sets the threshold for the green component of a pixel in in lin‐
150 eart color scan mode. Possible values are 1..255. The default
151 value is 128. This option is only available in scan mode color
152 lineart .
153 --threshold-blue
156 Sets the threshold for the blue component of a pixel in in lin‐
157 eart color scan mode. Possible values are 1..255. The default
158 value is 128. This option is only available in scan mode color
159 lineart.
160 --lightcolor
163 Sets the color of the light source. Possible values are white,
164 red, green and blue. The default value is white. This option
165 is only available in scan modes lineart color and color.
166
169 If a paper jam occurrs, the maintenance cover must be opened and
170 closed, even if the jammed paper can be removed without opening the
171 maintenance cover. Otherwise, the error condition will not be cleared.
172
175 The contents of the sharp.conf file is a list of options and device
176 names that correspond to Sharp scanners. Empty lines and lines begin‐
177 ning with a hash mark (#) are ignored. See sane-scsi(5) for details
178 about device names.
179 Lines setting an option start with the key word option, followed by the
181 option's name and the option's value. At present, three options are
182 defined: buffers, buffersize, and readqueue.
183 Options defined at the start of sharp.conf apply to all devices;
185 options defined after a device name apply to this device.
186 The options buffers and readqueue are only significant if the backend
188 has been compiled so that for each scan a second process is forked
189 (switch USE_FORK in sharp.c ). This process reads the scan data from
190 the scanner and writes this data into a block of shared memory. The
191 parent process reads the data from this memory block and delivers it to
192 the frontend. The options control the size and usage of this shared
193 memory block.
194 option buffers defines the number of buffers used. The smallest number
196 allowed is 2.
197 option buffersize defines the size of one buffer. Since each buffer is
199 filled with a single read command sent to the scanner, its size is lim‐
200 ited automatically to the size allowed by the operating system or by
201 the Sane SCSI library for SCSI read commands. A buffer size of 128 kB
202 or 256 kB is recommended for scan resolutions of 300 dpi and above.
203 option readqueue defines how many read commands to be sent to the scan‐
205 ner are queued. At present, the Sane SCSI library supports queued read
206 commands only for for Linux. For other operating systems, option read‐
207 queue should be set to 0. For Linux, option readqueue should be set to
208 2. Larger values than 2 for option readqueue are not reasonable in most
209 cases. option buffers should be greater than option readqueue.
210
213 This section focuses on the problem of stops of the scanner's carriage
214 during a scan. Carriage stops happen mainly with the JX-250. This scan‐
215 ner has obviously only a small internal buffer compared to its speed.
216 That means that the backend must read the data as fast as possible from
217 the scanner in order to avoid carriage stops.
218 Even the JX-250 needs only less than 10 seconds for a 400 dpi A4 gray
220 scale scan, which results in a data transfer rate of more than 1.6 MB
221 per second. This means that the data produced by the scanner must be
222 processed fairly fast. Due to the small internal buffer of the JX-250,
223 the backend must issue a read request for the next data block as soon
224 as possible after reading a block of data in order to avoid carriage
225 stops.
226 Stops of the carriage can be caused by the following reasons:
228 - too much "traffic" on the SCSI bus
230 - slow responses by the backend to the scanner,
231 - a program which processes the data acquired by the backend too
232 slow.
233 Too much "traffic" on the SCSI bus: This happens for example, if hard
235 disks are connected to the same SCSI bus as the scanner, and when data
236 transfer from/to these hard disks requires a considerable part of the
237 SCSI bandwidth during a scan. If this is the case, you should consider
238 to connect the scanner to a separate SCSI adapter.
239 Slow responses by the backend to the scanner: Unfortunately, UNIX-like
241 operating systems generally have no real time capabilities. Thus there
242 is no guarantee that the backend is under any circumstances able to
243 communicate with the scanner as fast as required. To minimize this
244 problem, the backend should be compiled so that a separate reader
245 process is forked: Make sure that USE_FORK is defined when you compile
246 sharp.c. If slow responses of the backend remain to be problem, you
247 could try to reduce the load of the system. Even while the backend and
248 the reader process need only a minor amount of processor time, other
249 running processes can cause an increase in the time delay between two
250 time slices given to the reader process. On slower systems, such an
251 increased delay can be enough to cause a carriage stop with the JX-250.
252 For Linux, the usage of the SG driver version 2.1.36 or above is recom‐
253 mended, because it supports, in combination with the SCSI library of
254 Sane version 1.0.2, command queueing within the kernel. This queueing
255 implementation, combined with a buffer size of at least 128 kB, should
256 avoid most carriage stops.
257 Slow processing of the scan data: An example for this situation is the
259 access to the scanner via a 10 MBit Ethernet, which is definitely too
260 slow to transfer the scan data as fast as they are produced by the
261 scanner. If you have enough memory available, you can increase option
262 buffers, so that an entire image can be stored in these buffers.
263 In order to see, if the backend is too slow or if the further process‐
265 ing of the data is too slow, set the environment variable
266 SANE_DEBUG_SHARP to 1. When a scan is finished, the backend writes the
267 line "buffer full conditions: nn" to stderr. If nn is zero, carriage
268 stops are caused by too slow responses of the backend or too much
269 "traffic" on the SCSI bus. If nn is greater than zero, the backend had
270 to wait nn times until a buffer has been processed by the frontend.
271 (Please note that option buffers must be greater than option readqueue
272 in order to get useful output for "buffer full conditions".)
273
276 /etc/sane.d/sharp.conf
277 The backend configuration file.
278 /usr/lib64/sane/libsane-sharp.a
280 The static library implementing this backend.
281 /usr/lib64/sane/libsane-sharp.so
283 The shared library implementing this backend (present on systems
284 that support dynamic loading).
285
287 SANE_DEBUG_SHARP
288 If the library was compiled with debug support enabled, this
289 environment variable controls the debug level for this backend.
290 E.g., a value of 128 requests all debug output to be printed.
291 Smaller levels reduce verbosity.
292
294 1. ADF Mode
295 After several ADF scans, the scanner moves the carriage back to
296 the idle position and back to ADF scan position, before a scan
297 starts. We do not know, if this is a problem of the scanner, or
298 if this is a bug of the backend. At present, the scanner must
299 power off and on to stop this annoying behaviour.
300 2. Threshold level does not work (only JX-610)
302 3. The maximum resolution is limited to 600 dpi(JX-610 supported to
304 1200 dpi) resp. 400 dpi (JX-250)
305 4. If the JX250 is used with an ADF, the following situation can occur:
307 After several scans, the scanner moves, after loading a new sheet of
308 paper, the carriage to the idle position, and then back to the position
309 used for ADF scans. This happens for every scan, in contrast to the
310 calibration, which is done after 10 scans. (For the calibration, the
311 carriage is also moved to the idle position.) We do not know if this
312 behavior is caused by the backend, or if it is a bug in the firmware of
313 the scanner.
314 5. Usage of a transparency adapter (film scan unit) is supported, but
316 not tested.
317
320 sane(7), sane-scsi(5)
321
324 Kazuya Fukuda, Abel Deuring
325
328 The Sharp backend is based on the Canon backend written by Helmut Koe‐
329 berle
330 Parts of this man page are a plain copy of sane-mustek(5) by David Mos‐
332 berger-Tang, Andreas Czechanowski and Andreas Bolsch
333 11 Jul 2008 sane-sharp(5)