Information
-
Patent Grant
-
6626107
-
Patent Number
6,626,107
-
Date Filed
Friday, June 15, 200123 years ago
-
Date Issued
Tuesday, September 30, 200320 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Hirshfeld; Andrew H.
- Nguyen; Anthony H.
Agents
- Blakely, Sokoloff, Taylor & Zafman
-
CPC
-
US Classifications
Field of Search
US
- 101 425
- 101 423
- 101 424
- 015 25651
- 015 25652
- 400 249
-
International Classifications
-
Abstract
A cleaning apparatus includes a cleaning cloth, supply shaft, take-up shaft, detector, projections, proximity switch, and catching detection unit. The cleaning cloth is pressed against a rotary member and cleans an outer surface of the rotary member. The cleaning web before cleaning is wound around the supply shaft. The supply shaft rotates in accordance with supply operation of the cleaning cloth to the outer surface of the rotary member. The take-up shaft is rotatably driven to take up the cleaning cloth supplied from the supply shaft to the outer surface of the rotary member. The detector, projections, and proximity switch output a signal corresponding to a rotational speed of the supply shaft. The catching detection unit detects that the cleaning cloth is caught in the rotary member on the basis of a state of the signal output from the detector, projections, and proximity switch. A method of detecting catching of the cleaning web in the cleaning apparatus is also disclosed.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a cleaning apparatus for cleaning an outer surface of a rotary member by pressing a cleaning web against it and, more particularly, to a catching detecting method and unit in the cleaning apparatus which detect that a cleaning web is caught in a rotary member.
In general, a printing press has a cleaning apparatus for cleaning the outer surface of a cylinder serving as a rotary member by urging a belt-like cleaning cloth against it. EP 0552856 (reference
1
) discloses a cleaning apparatus of this type, the main part of which is shown in FIG.
11
. Referring to
FIG. 11
, reference numeral
1
denotes the blanket cylinder of the printing press. A supply shaft
2
supplies a belt-like cleaning cloth
6
. A take-up shaft
3
takes up the cleaning cloth
6
. Guide rollers
4
and
5
guide the cleaning cloth
6
to the outer surface of the blanket cylinder
1
. A lever
8
is axially supported by a support pin
7
and detects that the cleaning cloth
6
is caught. A tension spring
11
has two ends respectively fixed by spring catches
9
and
10
. A limit switch
12
is actuated by the lever
8
.
The take-up shaft
3
intermittently takes up the cleaning cloth
6
supplied from the supply shaft
2
through the guide rollers
4
and
5
. In this cleaning apparatus, the cleaning cloth
6
intermittently traveling between the supply shaft
2
and take-up shaft
3
is pressed against the rotating blanket cylinder
1
in a taught state, so the outer surface of the blanket cylinder
1
is cleaned with it. At this time, since the blanket cylinder
1
is rotating, the cleaning cloth
6
might be caught in the blanket cylinder
1
during cleaning. In other words, the cleaning cloth
6
may adhesively attach to the blanket surface of the blanket cylinder
1
due to the viscosity of the ink, or may be torn up by some causes, so the cleaning cloth
6
is accidentally caught in the rotating blanket cylinder
1
.
In this case, in a conventional cleaning apparatus, the accident in which the cleaning cloth
6
is caught is detected in the following manner. When the cleaning cloth
6
is not caught, a distal end
8
b
of the lever
8
is pressed by the traveling cleaning cloth
6
because of the biasing force of the tension spring
11
, and the limit switch
12
is set in the non-operative state. When the cleaning cloth
6
is caught, the cleaning cloth
6
is loosened, so the lever
8
is rotated clockwise in
FIG. 11
by the biasing force of the tension spring
11
. A distal end
8
b
of the lever
8
then presses an actuator
12
a
of the limit switch
12
to turn on an internal contact.
In the above cleaning apparatus, the limit switch
12
detects that the lever
8
swings in accordance with a change in tension of the cleaning cloth
6
. Hence, when the cleaning cloth
6
is caught, if the tension of the cleaning cloth
6
does not change, accidental catching of the cleaning cloth
6
cannot be detected.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a cleaning apparatus which can reliably detect catching of a cleaning cloth even if the tension of the cleaning cloth does not change, and a method of detecting catching of the cleaning web in this apparatus.
In order to achieve the above object, according to the present invention, there is provided a cleaning apparatus comprising a cleaning web pressed against a rotary member and adapted to clean an outer surface of the rotary member, a supply shaft around which the cleaning web before cleaning is wound and which rotates in accordance with supply operation of the cleaning web to the outer surface of the rotary member, a take-up shaft rotatably driven to take up the cleaning web supplied from the supply shaft to the outer surface of the rotary member, signal output means for outputting a signal corresponding to a rotational speed of the supply shaft, and detection means for detecting that the cleaning web is caught in the rotary member on the basis of a state of the signal output from the signal output means.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A
is a side view showing the main part of a cleaning apparatus according to an embodiment of the present invention;
FIG. 1B
is an enlarged perspective view of the detector shown in
FIG. 1A
;
FIGS. 2A
to
2
C are timing charts showing the principle of catching detection during cleaning by the catching detection apparatus shown in
FIG. 1A
;
FIGS. 3A and 3B
are timing charts showing the principle of catching detection I during non-cleaning by the catching detection apparatus shown in
FIG. 1A
;
FIGS. 4A and 4B
are timing charts showing the principle of catching detection I during non-cleaning by the catching detection apparatus shown in
FIG. 1A
;
FIGS. 5A
to
5
C are timing charts showing the principle of catching detection II during non-cleaning by the catching detection apparatus shown in
FIG. 1A
;
FIGS. 6A
to
6
C are timing charts showing the principle of catching detection II during non-cleaning by the catching detection apparatus shown in
FIG. 1A
;
FIG. 7
is a block diagram of the catching detection apparatus shown in
FIG. 1A
;
FIG. 8
is a plan view of the display screen of the input/display unit shown in
FIG. 1A
;
FIG. 9
is a flow chart showing a catching detection process during cleaning and a catching detection process I during non-cleaning, which are performed by the CPU shown in
FIG. 7
;
FIG. 10
is a flow chart showing a catching detection process II during non-cleaning by the CPU shown in
FIG. 7
; and
FIG. 11
is a side view showing a conventional cleaning cloth catching detection apparatus.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention will be described in detail with reference to the accompanying drawings.
FIG. 1A
shows the main part of a cleaning apparatus according to an embodiment of the present invention. Referring to
FIG. 1A
, reference numeral
101
denotes a blanket cylinder of a printing press. A supply shaft
102
supplies a belt-like cleaning cloth
106
as a cleaning web. A take-up shaft
103
takes up the cleaning cloth
106
. Guide rollers
104
and
105
guide the cleaning cloth
106
to the outer surface of the blanket cylinder
101
. The take-up shaft
103
is intermittently pivoted by a ratchet mechanism so as to take up the cleaning cloth
106
supplied from the supply shaft
102
through the guide rollers
104
and
105
. At this time, the cleaning cloth
106
intermittently traveling between the supply shaft
102
and take-up shaft
103
is pressed against the rotating blanket cylinder
101
in a taut state, so the outer surface of the blanket cylinder
101
is cleaned with it. The supply shaft
102
is pivoted by the tension of the cleaning cloth
106
supplied to the outer surface of the blanket cylinder
101
as the take-up shaft
103
pivots.
The supply shaft
102
has a cylindrical detector
113
projecting from its one shaft end, as shown in FIG.
1
B. The detector
113
is rotated together with the supply shaft
102
. The detector
113
has eight magnetic metal projections
113
a
arranged equidistantly on its circumference and extending in the axial direction. A proximity switch
114
for magnetically detecting the projections
113
a
of the detector
113
as they pass is disposed to oppose the outer surface of the detector
113
. During rotation of the supply shaft
102
, the proximity switch
114
is ON while a projection
113
a
passes to output an “H”-level signal, and is OFF while the next projection
113
a
passes to output an “L”-level signal. In other words, the proximity switch
114
outputs a pulsed rotation signal, the output state of which alternately changes between “H” level and “L” level, to a catching detection unit
100
in accordance with rotation of the supply shaft
102
.
[Catching Detection During Cleaning]
In the cleaning apparatus with the above arrangement, abnormal travel of the cleaning cloth
106
during cleaning operation, which is caused by accidental catching or the like, is detected on the basis of the output state of the rotation signal supplied from the proximity switch
114
. More specifically, when the cleaning cloth
106
is caught in the blanket cylinder
101
, the supply shaft
102
rotates at a speed faster than that during normal cleaning as it is pulled by the caught cleaning cloth
106
. As the rotational speed of the supply shaft
102
increases, the number of output pulses from the proximity switch
114
within a predetermined period of time also increases.
The catching detection unit
100
counts the pulses of the rotation signal supplied from the proximity switch
114
. When the pulse count exceeds a preset value within a predetermined period of time, i.e., when the rotational speed of the supply shaft
2
exceeds a predetermined value, the catching detection unit
100
determines that the cleaning cloth
106
is caught in the blanket cylinder
101
.
In the above example, whether the cleaning cloth
106
is caught is checked by counting the output pulses within the predetermined period of time. Alternatively, the catching detection unit
100
may determine that the cleaning cloth
106
is caught in the blanket cylinder
101
when the frequency of the rotation signal exceeds a predetermined frequency at least once or continuously for a predetermined period of time. When the cleaning cloth
106
is caught in the blanket cylinder
101
, the rotational speed of the supply shaft
102
increases, and the frequency of the rotation signal also increases. Hence, a traveling trouble of the cleaning cloth
106
caused when the cleaning cloth
106
is caught in the blanket cylinder
101
can be detected in the same manner by checking whether or not the frequency of the rotation signal exceeds the predetermined value.
FIGS. 2A
to
2
C show timing charts for detecting catching during cleaning operation. As shown in
FIGS. 2A and 2B
, the number of times the rotation signal from the proximity switch
114
rises to “H” level, i.e., the number of times the proximity switch
114
is turned on, within a predetermined period of time T counted by the timer is counted. When this count becomes 4 or more during the predetermined period of time T, an “H”-level detection signal indicating that the cleaning cloth
106
is caught in the blanket cylinder
101
is output, as shown in FIG.
2
C.
[Catching Detection I During Non-Cleaning (Wait Mode After Cleaning Is Ended)]
Catching of the cleaning cloth
106
during non-cleaning operation is also detected on the basis of the output state of the rotation signal supplied from the proximity switch
114
. More specifically, when cleaning operation is ended, take-up operation for the cleaning cloth
106
by the take-up shaft
103
is stopped, and the cleaning cloth
106
is separated from the outer surface of the blanket cylinder
101
. At this time, during a state wherein the printing press keeps operation, i.e., in the wait mode in a state wherein the blanket cylinder
101
is kept rotating, the cleaning cloth
106
is accidentally caught in the blanket cylinder
101
by some cause.
As a countermeasure for this, the output state (“H” or “L” level) of the rotation signal from the proximity switch
114
is stored with the supply shaft
102
being stopped at the end of cleaning. The stored output state of the rotation signal and the output state of the rotation signal in the wait mode are compared. If the output states differ, it is determined that the cleaning cloth
106
is caught in the blanket cylinder
101
.
FIGS. 3A and 3B
, and
FIGS. 4A and 4B
show timing charts of catching detection I during non-cleaning operation.
FIG. 3A
shows a case wherein the rotation signal is at “L” level at time t
0
at the end of cleaning, i.e., a case wherein the proximity switch
114
is OFF and the supply shaft
102
is stopped.
FIG. 4A
shows a case wherein the rotation signal is at “H” level at time t
0
at the end of cleaning, i.e., a case wherein the proximity switch
114
is ON and the supply shaft
102
is stopped.
As shown in
FIG. 3A
, in the wait mode after cleaning is ended, when the cleaning cloth
106
is caught in the blanket cylinder
101
, the supply shaft
102
pivots, and the rotation signal from the proximity switch
114
becomes “H” level at time t
0
. In this case, since the signal level in the wait mode changes from the one (storage level) obtained at the end of cleaning, an “H”-level detection signal is output, as shown in FIG.
3
B.
As shown in
FIG. 4A
, in the wait mode after cleaning is ended, when the cleaning cloth
106
is caught in the blanket cylinder
101
, the supply shaft
102
pivots, and the rotation signal from the proximity switch
114
becomes “L” level at time t
1
. In this case, since the signal level in the wait mode changes from the one (storage level) obtained at the end of cleaning, an “H”-level detection signal is output, as shown in FIG.
4
B.
[Catching Detection II During Non-Cleaning (Wait Mode After Cleaning Is Ended)]
Catching detection operation I is subject to erroneous detection due to vibration or impact. More specifically, when the output state of the rotation signal from the proximity switch
114
at the end of cleaning changes only once, it is determined that catching occurs. For example, when the supply shaft
102
is kept stopped at the boundary between ON and OFF of the proximity switch
114
and pivots slightly due to vibration or impact, so the proximity switch
114
changes from the ON state to the OFF state, or from the OFF state to the ON state, a catching detection signal is erroneously output.
In order to avoid such erroneous detection, the output state (“H” or “L” level) of the rotation signal from the supply shaft
102
while the supply shaft
102
is kept stopped at the end of cleaning is stored. After that, when the output state of the rotation signal changes, the time point at which the output state, after having changed once, is restored to the initial output state obtained at the end of cleaning is set as the origin. Then, whether or not the supply shaft
102
is caught in the blanket cylinder
101
is checked on the basis of the output state of the rotation signal obtained at a lapse of a predetermined period of time from the preset origin.
FIGS. 5A
to
5
C, and
FIGS. 6A
to
6
C show timing charts of catching detection II during non-cleaning operation.
FIG. 5A
shows a case wherein the rotation signal is at “L” level at time t
0
at the end of cleaning, i.e., a case wherein the proximity switch
114
is OFF and the supply shaft
102
is stopped.
FIG. 6A
shows a case wherein the rotation signal is at “H” level at time t
0
at the end of cleaning, i.e., a case wherein the proximity switch
114
is ON and the supply shaft
102
is stopped.
As shown in
FIG. 5A
, in the wait mode after cleaning is ended, after the rotation signal from the proximity switch
114
changes from “L” level to “H” level once at time t
1
, when it is restored at time t
2
to “L” level (storage level) equal to the output state at the end of cleaning, time t
2
is set as the origin. Then, as shown in
FIG. 5B
, when a predetermined period of time TM (e.g., 100 msec) has elapsed from time t
2
as the origin, whether or not the output state of the rotation signal is “H” level is checked. If the output state of the rotation signal is “H” level at time t
2
, an “H”-level detection signal indicating that the cleaning cloth
106
is caught in the blanket cylinder
101
is output, as shown in FIG.
5
C.
As shown in
FIG. 6A
, in the wait mode after cleaning is ended, after the rotation signal from the proximity switch
114
changes from “H” level to “L” level once at time t
1
, when it is restored at time t
2
to “H” level (storage level) equal to the output state at the end of cleaning, time t
2
is set as the origin. Then, as shown in
FIG. 6B
, when a predetermined period of time TM (e.g., 100 msec) has elapsed from time t
2
as the origin, whether or not the output state of the rotation signal is “H” level is checked. If the output state of the rotation signal is “H” level at time t
2
, an “H”-level detection signal indicating that the cleaning cloth
106
is caught in the blanket cylinder
101
is output, as shown in FIG.
6
C.
The “H” level at a lapse of the predetermined period of time TM from time t
2
is checked, because the speed at which the cleaning cloth
106
is caught is fast and the rotation signal does not form a pulse signal due to the input-response speed of the proximity switch
114
. More specifically, when the cleaning cloth
106
is caught at a high speed, the rotation signal from the proximity switch
114
at first repeats level change between “H” and “L” and then readily stays at “H” level. For this reason, in
FIGS. 5A
to
5
C and
FIGS. 6A
to
6
C, the level of the rotation signal at a lapse of the predetermined period of time TM from time t
2
is checked, and when the rotation signal is “H” level, it is determined that catching has occurred.
In
FIG. 6A
, when the supply shaft
102
slightly rotates at time t
1
due to vibration or impact, the rotation signal from the proximity switch
114
changes from “H” level to “L” level, and the supply shaft
102
that has rotated slightly is sometimes restored to the initial state. In this case as well, counting of the predetermined period of time TM is started with respect to the time point, at which the rotation signal from the proximity switch
114
changes to “H” level after having changed from “L” level to “H” level, as the origin. As the level of the rotation signal at a lapse of the predetermined period of time TM is “H” level, an erroneous catching detection signal is output.
In order so solve this problem, the supply shaft
102
may constantly be lightly braked, so if it has rotated slightly due to vibration or impact, it will not be easily restored to the initial state. Then, the supply shaft
102
that has rotated slightly due to vibration or impact is not restored to the initial state, and no erroneous signal is output.
FIG. 7
shows a catching detection unit
100
which performs catching detection in accordance with the principle described above. The catching detection unit
100
has the proximity switch
114
described above, a CPU (Central Processing Unit)
115
for performing a catching detection process, a ROM (Read Only Memory)
116
storing a catching detection program, a RAM (Random Access Memory)
117
, a preset value storage memory
118
for storing a preset value A required when performing catching detection during cleaning, interfaces (I/Os)
119
to
121
for performing various types of interface operations, a waveform shaper
122
for shaping the waveform of the rotation signal from the proximity switch
114
, and a touch panel type input/display unit
123
.
The CPU
115
performs a catching detection process on the basis of the rotation signal supplied from the proximity switch
114
in accordance with the catching detection program stored in the ROM
116
while accessing the RAM
117
and preset value storage memory
118
. The detection result is supplied to a printing press control unit
200
through the interface
121
.
A catching detection process during cleaning and a catching detection process I during non-cleaning by the CPU
115
will be described with reference to the flow chart shown in FIG.
9
.
[Catching Detection During Cleaning (
FIGS. 2A
to
2
C)]
When cleaning is started, after steps S
901
and S
902
, the CPU
115
sets a count C of the counter to 0 (step S
903
), and starts the count operation of a soft timer (counter) (step S
904
). The CPU
115
then checks the output state of the rotation signal supplied from the proximity switch
114
(step S
905
). If the rotation signal rises to “H” level, i.e., when a pulse is generated, the CPU
115
sets the count C to C+1 (step S
906
). The CPU
115
then reads out the preset value A from the memory
118
(step S
907
), and compares the count C with preset value A (step S
908
).
If the count C is equal to or less than the preset value A, the CPU
115
checks the count of the soft timer which is counting (step S
909
). If the count of the soft timer does not reach a predetermined value T, the flow returns to step S
905
. Steps S
905
to S
909
are repeated in the similar manner. If the count C>preset value A is obtained before the count of the soft timer reaches the predetermined value T, the CPU
115
outputs a catching detection signal indicating that the cleaning cloth
106
is caught to the printing press control unit
200
. Upon reception of the catching detection signal, the printing press control unit
200
immediately stops the printing press and cleaning apparatus (step S
910
). Thus, rotation of the blanket cylinder
101
is stopped, and the take-up operation for the cleaning cloth
106
by the take-up shaft
103
is also stopped.
When it is detected that the cleaning cloth
106
is caught, the CPU
115
supplies a display command to the input/display unit
123
to display that catching has occurred in a specific one of the plurality of printing units. Simultaneously, the CPU
115
drives an alarm unit (not shown) to produce an alarm sound.
FIG. 8
shows the display screen of the input/display unit
123
. Referring to
FIG. 8
, block lamps
23
-
1
to
23
-
8
indicating the eight printing units are turned on to inform a printing unit in which catching has occurred. When either one of the block lamps
23
-
1
to
23
-
8
is turned on, neither the printing press can be rotated nor the cleaning apparatus can be operated. When a reset button
23
-
9
is pressed, the inhibit state is canceled, and the printing press and cleaning apparatus can be operated.
[Catching Detection I During Non-Cleaning (Wait Mode After Cleaning Is Ended) (
FIGS. 3A and 3B
, and FIGS.
4
A and
4
B)]
When cleaning is ended in step S
902
, the CPU
115
reads the output state (“H”/“L” level) of the rotation signal supplied from the proximity switch
114
at the end of cleaning as S
0
, and stores it in the RAM
117
(step S
911
). Then, the CPU
115
reads the output state of the rotation signal supplied from the proximity switch
114
again as S (step S
912
), and compares the output state S with the output state S
0
stored in the RAM
117
(step S
913
).
If the two output states S and S
0
coincide, that is, if the output state S
0
at the end of cleaning which is read in step S
911
coincides with the output state S in the wait mode after cleaning is ended, which is read in step S
912
, it is checked whether or not the printing press is in operation (step S
914
). If the printing press is in operation, the flow returns to step S
912
, and steps S
912
to S
914
are repeated. During this repetition, if the two output states S and S
0
do not coincide in step S
913
, that is, if the output state of the rotation signal from the proximity switch
114
changes, the flow advances to step S
910
, and the printing press and cleaning apparatus are stopped.
A catching detection process II during non-cleaning will be described with reference to the flow chart of FIG.
10
.
FIG. 10
corresponds to steps S
911
to S
914
of FIG.
9
.
[Catching Detection II During Non-Cleaning (Wait Mode After Cleaning Is Ended) (
FIGS. 5A
to
5
C, and
FIGS. 6A
to
6
C)]
When cleaning is ended in step S
902
, the CPU
115
reads the output state of the rotation signal supplied from the proximity switch
114
at the end of cleaning. The CPU
115
then checks whether the output state of the read rotation signal is “H” level or “L” level (step S
102
). More specifically, the CPU
115
checks whether the proximity switch
114
is OFF and the supply shaft
102
is stopped, or the proximity switch
114
is ON and the supply shaft
102
is stopped.
If the output state of the rotation signal is “L” level, the CPU
115
confirms in step S
103
that the printing press is in operation, and reads the output state of the rotation signal supplied from the proximity switch
114
again (step S
104
). Then, the CPU
115
checks the read output state (step S
105
). If the output state is “H” level, i.e., if the output state of the rotation signal has changed from “L” level to “H” level, the CPU
115
performs a process similar to that described above in order to check whether or not the “H”-level output state has changed to “L” level again (steps S
106
to S
108
). If a change to “L” level has occurred, the soft timer starts counting (step S
109
).
Then, the CPU
115
confirms in step S
110
that the printing press is in operation, and checks whether or not the soft timer in counting operation has reached the predetermined value TM (step S
111
). If YES, the CPU
115
reads the output state of the rotation signal supplied from the proximity switch
114
(step S
112
), and checks whether or not the output state is “H” level (step S
113
). If YES, the operations of the printing press and cleaning apparatus are stopped (step S
114
). If NO, the flow returns to step S
103
, and the processes of steps S
103
to S
113
are repeated.
In step S
102
, if the output state of the rotation signal is “H” level, the CPU
115
confirms in step S
115
that the printing press is in operation, and reads the output state of the rotation signal supplied from the proximity switch
114
again (step S
116
). Then, the CPU
115
checks the read output state (step S
117
). If the output state is “L” level, i.e., if the output state of the rotation signal has changed from “H” level to “L” level, the CPU
115
performs a process similar to that described above in order to check whether or not the “L”-level output state has changed to “H” level again (steps S
118
to S
120
). If a change to “L” level has occurred, the soft timer starts counting (step S
121
).
Then, the CPU
115
confirms in step S
122
that the printing press is in operation, and checks whether or not the soft timer in counting operation has reached the predetermined value TM (step S
123
). If YES, the CPU
115
reads the output state of the rotation signal supplied from the proximity switch
114
(step S
124
), and checks whether or not the output state is “H” level (step S
125
). If the output state is “H” level, the operations of the printing press and cleaning apparatus are stopped (step S
114
). If the output state is “L” level, the flow returns to step S
115
, and the processes of steps S
115
to S
125
are repeated.
In the above embodiment, the catching detection process during non-cleaning is performed by the method described with reference to
FIGS. 3A and 3B
and
FIGS. 4A and 4B
, or
FIGS. 5A
to
5
C and
FIGS. 6A
to
6
C. Alternatively, even during non-cleaning, catching detection may be performed in accordance with the method described with reference to FIG.
2
.
In the catching detection process during cleaning described with reference to
FIG. 2
, the pulse count of the rotation signal and the preset value are constantly compared within the predetermined period of time T. Alternatively, the pulse count of the rotation signal and the preset value may be compared when the predetermined period of time T has elapsed.
In the above embodiment, the rotary member to be cleaned is a blanket cylinder. However, the rotary member is not limited to a blanket cylinder. For example, catching of the cleaning cloth in a printing cylinder other than a blanket cylinder, e.g., an impression cylinder, a transfer cylinder, or a delivery cylinder, and catching of the cleaning cloth in a roller such as a form roller or oscillating roller can be performed in the same manner as that described above.
In the above embodiment, the rotation signal is magnetically obtained by using the proximity switch
114
. Alternatively, an optical sensor such as a reflection sensor, or a mechanical sensor such as a limit switch may be used instead. The rotation signal, the output state of which changes in accordance with rotation of the supply shaft
102
, is not necessarily a pulse signal, and it suffices as far as the rotation signal is a signal that changes periodically like a triangular wave or sinusoidal wave.
In the above embodiment, the catching detection process by the catching detection unit
100
is performed in a software manner using the CPU
115
. Alternatively, this process may be performed with hardware comprised of a counter circuit, a timer circuit, a comparator, and the like.
As has been described above, according to the present invention, even when the tension of the cleaning cloth does not change, the accident that the cleaning cloth is caught in the rotary member as a cleaning target during cleaning can be reliably detected. Even in the wait mode after cleaning is ended, catching of the cleaning cloth can be detected reliably at an early state. In the wait mode after cleaning is ended, catching of the cleaning cloth can be detected without performing erroneous detection due to vibration or impact.
Claims
- 1. A cleaning apparatus comprising:a cleaning web pressed against a rotary member and adapted to clean an outer surface of said rotary member; a supply shaft around which said cleaning web before cleaning is wound and which rotates in accordance with supply operation of said cleaning web to the outer surface of said rotary member; a take-up shaft rotatably driven to take up said cleaning web supplied from said supply shaft to the outer surface of said rotary member; signal output means for outputting a signal corresponding to rotation of said supply shaft; and detection means for detecting that said cleaning web is caught in said rotary member on the basis of a state of the signal output from said signal output means, wherein said signal output means outputs the signal an output state of which changes periodically in accordance with rotation of said supply shaft, wherein said apparatus further comprises storage means for storing the output state of the signal supplied from said signal output means in a state wherein said supply shaft is stopped when cleaning is ended, and said detection means comprises comparing means for comparing the output state of the signal, obtained when cleaning is ended, stored by said storage means with an output state of the signal in a wait mode after cleaning is ended, and outputting a catching detection signal indicating that said cleaning web is caught in the rotary member when the output states differ.
- 2. An apparatus according to claim 1, wherein said signal output means comprisesa detector with a plurality of detecting portions arranged equidistantly on an outer surface thereof and rotatable together with the rotary member, and a detection element for detecting the detecting portions, when said detector rotates, in accordance with either one of magnetic, optical, and mechanical methods, and outputting a rotation signal of said detector.
- 3. An apparatus according to claim 1, wherein said rotary member is either one of a cylinder and a roller of a printing press.
- 4. An apparatus according to claim 1, herein the output state stored in the storage means provides an indication of a rotational position of the supply shaft when the supply shaft has stopped at the end of cleaning.
- 5. A method of detecting catching of a cleaning web in a cleaning apparatus comprising a cleaning web pressed against a rotary member and adapted to clean an outer surface of the rotary member, a take-up shaft for taking up the cleaning web that has cleaned the outer surface of the rotary member, a supply shaft around which the cleaning web to be supplied to the outer surface of the rotary member is wound and which is rotated by take-up operation of the take-up shaft so as to supply the cleaning web, said detection method comprising the steps of:outputting a signal corresponding to rotation of the supply shaft; and detecting that the cleaning web is caught in the rotary member on the basis of an output state of the signal corresponding to the rotation, wherein the outputting step comprises the step of outputting a signal an output state of which changes periodically in accordance with rotation of the supply shaft, wherein the detecting step comprises the steps of setting, as an origin, a time point at which the output state of the signal supplied from the signal output means, after having changed once, is restored to an initial output state, in the state wherein the supply shaft is stopped when cleaning is ended, and outputting a catching detection signal indicating that the cleaning web is caught in the rotary member on the basis of the output state of the signal obtained at a lapse of a predetermined period of time from the preset origin.
- 6. A cleaning apparatus comprising:a cleaning web pressed against a rotary member and adapted to clean an outer surface of said rotary member; a supply shaft around which said cleaning web before cleaning is wound and which rotates in accordance with supply operation of said cleaning web to the outer surface of said rotary member; a take-up shaft rotatably driven to take up said cleaning web supplied from said supply shaft to the outer surface of said rotary member; signal output means for outputting a signal corresponding to rotation of said supply shaft; and detection means for detecting that said cleaning web is caught in said rotary member on the basis of a state of the signal output from said signal output means, wherein said signal output means outputs the signal an output state of which changes periodically in accordance with rotation of said supply shaft, wherein said detection means sets, as an origin, a time point at which the output state of the signal supplied from said signal output means, after having changed once, is restored to an initial output state, in the state wherein said supply shaft is stopped when cleaning is ended, and outputs a catching detection signal indicating that said cleaning web is caught in the rotary member on the basis of the output state of the signal obtained at a lapse of a predetermined period of time from the preset origin.
- 7. An apparatus according to claim 6, wherein said signal output means comprisesa detector with a plurality of detecting portions arranged equidistantly on an outer surface thereof and rotatable together with the rotary member, and a detection element for detecting the detecting portions, when said detector rotates, in accordance with either one of magnetic, optical, and mechanical methods, and outputting a rotation signal of said detector.
- 8. An apparatus according to claim 6, wherein said rotary member is either one of a cylinder and a roller of a printing press.
- 9. A method of detecting catching of a cleaning web in a cleaning apparatus comprising a cleaning web pressed against a rotary member and adapted to clean an outer surface of the rotary member, a take-up shaft for taking up the cleaning web that has cleaned the outer surface of the rotary member, a supply shaft around which the cleaning web to be supplied to the outer surface of the rotary member is wound and which is rotated by take-up operation of the take-up shaft so as to supply the cleaning web, said detection method comprising the steps of:outputting a signal corresponding to rotation of the supply shaft; and detecting that the cleaning web is caught in the rotary member on the basis of an output state of the signal corresponding to the rotation; wherein the outputting step comprises the step of outputting a signal an output state of which changes periodically in accordance with rotation of the supply shaft, wherein the method further comprises the step of storing the output state of the signal supplied from said signal output means in a state wherein the supply shaft is stopped when cleaning is ended, and the detecting step comprises the steps of comparing the stored output state of the signal, obtained when cleaning is ended, with an output state of the signal in a wait mode after cleaning is ended, and outputting a catching detection signal indicating that the cleaning web is caught in the rotary member when the output states differ.
- 10. A method according to claim 9, wherein the stored output state provides an indication of a rotation position of the supply shaft when the supply shaft has stopped at the end of cleaning.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-188316 |
Jun 2000 |
JP |
|
US Referenced Citations (6)
Foreign Referenced Citations (4)
Number |
Date |
Country |
29611014 |
Aug 1996 |
DE |
0291745 |
Nov 1988 |
EP |
0552856 |
Jul 1993 |
EP |
0307036 |
Nov 1992 |
JP |