CA1173890A - Control of copier start-up operations - Google Patents
Control of copier start-up operationsInfo
- Publication number
- CA1173890A CA1173890A CA000380146A CA380146A CA1173890A CA 1173890 A CA1173890 A CA 1173890A CA 000380146 A CA000380146 A CA 000380146A CA 380146 A CA380146 A CA 380146A CA 1173890 A CA1173890 A CA 1173890A
- Authority
- CA
- Canada
- Prior art keywords
- copier
- photosensitive surface
- switch
- timing wheel
- cleaning
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 238000004140 cleaning Methods 0.000 claims description 60
- 230000007704 transition Effects 0.000 claims description 31
- 230000003213 activating effect Effects 0.000 claims description 25
- 238000000034 method Methods 0.000 claims description 9
- 230000003287 optical effect Effects 0.000 claims description 6
- 230000000977 initiatory effect Effects 0.000 claims 4
- 230000001131 transforming effect Effects 0.000 claims 3
- 238000009877 rendering Methods 0.000 claims 2
- 241001354243 Corona Species 0.000 description 22
- 238000013459 approach Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000002093 peripheral effect Effects 0.000 description 4
- 238000013461 design Methods 0.000 description 3
- 230000009977 dual effect Effects 0.000 description 3
- 238000012546 transfer Methods 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 2
- 239000000835 fiber Substances 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 238000005286 illumination Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 230000002159 abnormal effect Effects 0.000 description 1
- 239000000872 buffer Substances 0.000 description 1
- 230000005591 charge neutralization Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000009979 protective mechanism Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 230000003068 static effect Effects 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
- G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
- G03G21/0005—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge for removing solid developer or debris from the electrographic recording medium
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Control Or Security For Electrophotography (AREA)
- Combination Of More Than One Step In Electrophotography (AREA)
Abstract
Abstract The start-up of copier operations is controlled according to the position of the copier's photosen-sitive drum when power to the copier was shut-off, without the need for special memory elements for storing the photosensitive drum's position upon power shut-off.
Description
BO980-OU'J
~173~390 Description -CONTROL`OF COPIER START-UP OPERATIONS
Technical Field This invention generally relates to a copier, and more particularly to copier start-up operations control..
It is well known that xerographic copiers include a photosensitive surface which is charged to a uniform potential and then exposed to an image to form a latent electrostatic image. The latent electrostatic image is developed by application of toner thereto. The developed image is transferred to an output medium, generally a - copy paper, and then fixed thereto to produce a permanent copy. Xerographic copiers also include cleaning means employing brushes and/or other means to remove any residual toner left on the photosensitive surface, and neutralize any residual charge left thereon prior to using the photosensitive surface for making a new copy.
In a normal copier cycle, the photosensitive surface,is sequentially moved past a charging station, exposure station, developing station, transfer station and cleaning station. After passing the cleaning station the photosensitive surface i9 returned to its initial position adjacent the charging station, and new copier cycle may begin if further copying is desired. If further copying is not desired, the copier is turned off at the conclusion of the normal copier cycle.
As is well known, the normal copier cycle described above is often interrupted. Power to the copier may be interrupted because of a loss of electrical power due to a power failure or the inadvertent switching off of the main copier switch. More commonly, con-temporary copiers include a protective mechanism which shuts-off the copier upon the occurrence of a paper jam or other abnormal condition during the 7~90 copier cycle. Regardless of whether the copier is shut off under normal eond;tions at the conclusion of a copier cycle, or was interrupted in midstream, means must be provided to control copier start-up upon reappliçation of power. The copier mus-t be available for copy production as quickly as possible upon reapplieation of power, and the initial eopy must be of the same high quality as all subsequent eopies. !i!
A simple control of copier start-up would always elean the photosensitive surfaee upon reapplication of power to ensure that the initial copy is of high quality. Production of copies would be delayed until the photosensitive surface is passed by the cleaning 15 station. It is apparent that this simple start-up control is a waste of time and energy. At the end of a normal copier cycle, the photosensitive surface has already been cleaned, and there is no need to reelean the surfaee when power is reapplied. On the other 20 hand, if copier operation is interrupted in midstream for any of the reasons discussed above, the photo-sensitive surface must be cleaned and prepared before further copying may commence upon reapplication of power.
It is therefore desirable for copier start-up to vary, depending upon the condition upon whieh the eopier previously shut down. If the copier shut down at the end of a normal copieX cyele, eopying may begin immediately upon the reapplieation of power.
30 Time and energy need not be wasted in eleaning an already clean photosensitive surfaee. If, on the other hand, the eopier shut down in the middle of a eopier eycle, eopying may not begin until the photo-sensitive surfaee is cleaned. While the initial 35 eleaning produees a slight delay before produetion of the initial copy, failure to clean the photosensitive surface will result in an initial copy of unacceptable quality.
BO980-009 ~ 9 O
Background A
In the past, large and expensive copiers included special memory elements. These memory elements were relays, mechanical latches, battery powered memory elements or non-volatile read/write memory elements.
When power was removed from the copier, an indication of the point in the copier cycle at which power was removed was stored in the special memory elements. The special memory elements would retain this information while power was removed from the copier. When power was reapplied, copier operations would start up in accordance with the status of the copier prior to power shut-off as specified by the special memory elements. If power was interrupted at the end of a normal copier cycle, copy production would immediately be enabled. If power was interrupted in the middle of a copier cycle, cleaning of the photosensitive surface would take place prior to the production of an initial copy.
Special memory elements, whether mechani_al or electrical, are too expensive and complex to meet the design objectives of a low cost, compact copier. In one form of special memory element, electrical power is maintained at the special memory element even when power is removed from the remainder of the copier. This poses a safety hazard to the copier operator who must open the copier to clear a paper jam, and may receive a shoclc if he touches that part of the copier at which power is still maintained. Other forms of special memory elements employ a battery to retain the information when the copier is shut off. While eliminating any shock hazard, battery powered special memory elements are complex and take up an excess of space in a compact copier. Still vther forms cf special memory elements which do not require electric or battery power are prohibitively expensive for a low cost copier.
In designing a low cost copier, it is desirable to eliminate special memory elements while still controlling copier start-up operations depending upon the last-1iO980-009 .~17~
.~
powered-on state of the co~ier. It is especially desirable to accomplish thi,s control of copier start-up operations through the modification of components already present in the copier. By eliminating special memory elements, the complexity of the copier and the cost thereof may be reduced. By integrating the copier start-up control into preexisting copier components, the benefits of control of copier start-up may be attained with little or no cost increase.
Disclosure of Invention It is an object of the invention to provide improved control of copier start-up operations.
It is another object of the invention to provide control of copier start-up operations without the use of special memory elements for storing the last-powered-on state.
It is another object of the invention to provide control of copier start-up by merely modifyir.g already present copier components.
It is another object of the invention to provide control'of copier start-up which initiates photo-sensitive surface cleaning prior to enabling copy production if the last-powered-on state of the copier was in the middle of a normal copier cycle.
It is still a further object of the invention to provide control of copier start-up which enables immediate copying of a document if the power was removed from the copier after the end of a normal copier cycle.
The,se and other objects are accomplished by providing an indicating means which is responsive to the position of the photosensitive surface. If the photosensitive surface is in its position at the end of a normal copier cycle, i.e., its position after the photosensitive surface has been cleaned, the indicating means provides a first indication. If the photosensitive surface is in any position other than its position at ~0980-009 ~1~'7~
5_ the end of a normal copier cycle, -the indicating means provides a second indication. When power is applied to the copier, the state of the indicating means is ascertained. If the first indicaticn is present, thus signifying that the copier was shut off at the end of a normal copier cycle, immediate copy production is enabled. If the second indication is present, thus signifying the copier was shut off at some point during a copier cycle, production of copies is inhibited and the photosensitive surface is cleaned. Normal copy production is then enabled.
In a first embodiment the photosensitive surface is a drum, and a timing wheel is mounted coaxially with the drum for rotation therewith. The timing wheel has a cam on the periphery thereof. A switch is mounted adjacent the timing wheel to engage the cam when the drum is in its position at the end of a normal copier cycle. The switch provides the first lndication when it engayes the cam and the second indication at all other times.
In a second embodiment a timing wheel is already present in the copier to supply synchronization informatlon for use by the copler controller ln controlllng and synchronizing copy producing operations.
The periphery of the timing wheel has a series of small cams to provide synchronization information.
Copier start-up information is provided by adding a single large indicatlng cam to the already e~lsting timing wheel. Means are also provlded for the copier to distinguish between the large indicating cam and the small synchronization cams.
In a thlrd embodiment the timing wheel is also already present in the copier to supply synchronization inform~tion. The side of the timlng wheel has a series of cams in a circular pattern thereon. Synchron-izatlon informatlon ls provided by individual camsdisplaced at various points in the circular pattern.
Copier start-up indicating information is provided by the addition of a pair of closely spaced cams at a -G-predetermined position in the circular pattern.
~5eans are provided for the copier to distinguish between the individual synchronization cams and the pair of closely spaced indicating cams.
In all embodiments, the indicating cam or cams and switch provide means for controlling copier start-up without the necessity of special memory elements to remember the last-powered-on state of the copier.
Brief Description _ the Drawing Fig. 1 is a schematic representation of a copier having a first embodiment of t,he invention.
- Fig. 2 is a cross sectional view of the timing wheel of a second embodiment of the. invention.
Fig. 3 is a flow char-t representation of the control of copier start-up operations in a copier employing the timing wheel of Fig. 2.
Fig. 4 shown with Fig. 2 is a cross sectional view of the timing wheel of a third embociment of the invention.
Fig. 5 is a flow chart representation of the control of copier start-up operations in a copier employing the timing wheel of Fig. 4.
Best ~50de f Carrying Out the Invention Although the subject invention may be employed in any xerographiG copier, it will be described with respect to a xerographic copier having the configuration of Fig. 1. Xerographic copier 10 generally comprises photosensitive surface 11, here the perhiphery of photosensitive drum 12, mounted on shaft 13 for rotation in the counterclockwise direction by motor 14. Copier 10 is designed to be compact and low cost. To reduce the number of copier components, many of these components are designed to serve a dual purpose in the copying process, as will be described below.
A normal copier cycle will now be described.
Reference point 16 will be employed for the purposes _ _ ~0~80-009 ~ ~73~o of describing the rotation of the photosensitive drum 12 past the copier components. It will be understood that reference point 16 is not actually present on photosensitive drum. For the purposes of illustrating a normal copier cycle, it will also be assumed that the copier was turned off at the conclusion of a previous normal copying cycle. When this is the case, photosensitive drum 12 will always be at its position shown in Fig. 1, i.e., reference point 16 10 will be adjacent corona 17.
To begin the normal copier cycle copier controller 18 initiates rotation of drum 12 in the counterclock-wise direction by activating motor 14. Reference point 16 passes corona 17. Corona 17, under the 15 control of copier controller 18, charges photosensitive surface 11 to a very high negative voltage. Rotation continues and reference point 16 passes corona 19.
Under the control of copier controller 18, corona 19 smooths the charge on photosensitive surface 11 so 20 that it is uniform throughout the photosensitive surface.
Photosensitive drum 12 continues to rotate until reference point 16 approaches copier optics 21.
Copier optics assembly 21 is represented schemmatically 25 by optic element 22, which may be a fiber optics bundle, for examp]e. Copier optics assembly further includes document glass 23, illumination means 25, mirror 28 and roller pairs 24 and 26. When reference point 16 approaches fiber optics element 22, copier 30 controller 18 activates roller pairs 24 and 26 to move the document to be copied across document glass 23 from Eoller pair 24 to roller pair 26, at the same speed as the peripheral speed of photosensitive surface 11. Illumination means 25 is turned on and 35 optic element 22 scans the document to be copied and forms a latent electrostatic image on the photo-sensitive surface 11.
Bo98o-oo9 ~1 7~
Continuing its counterclockwise rotation, reference point 16 approaches magnetic brush 27. Under the control of controller 18, magnetic brush 27 develops the latent electrostatic image by applying toner to the charged portions of the photosensitive surface.
Rotation of the drum continues and reference point 16 approaches corona 17 for the second time. As reference point 16 approaches corona 17, copier controller 18 causes a sheet of copy paper to be picked from paper supply 29 and to travel along paper path 31. The copy paper sheet and reference point 16 approach corona 17 simultaneously, at the same linear speed.
Corona 17 which was previously employed as part - of the charging station now acts as a transfer station Corona 17 transfers the toner from the surface 11 of photosensitive drum 12 to the copy paper. The copy paper continues along paper path 32 and encounters fuser station 33, here represented by fuser roller pair.34 Through a combination of heat and/or pressure, rollers 34 permanently fuse the toner to the copy paper.
The sequence of operations described above, beginning with reference point 16 passing corona 17 for the first time and ending after point 16 has passed corona 17 for the second time constitute the copy producing portion of a normal copier cycle.
Rotation of photosensitive drum 12 continues and reference point 16 approaches corona 19 for the second time. This is the beginning of the cleaning portion of a normal copier cycle. Corona 19 is now employed to remove any residual charge left on photo-sensitive surface 11. Further discharging of photo-sensitive surface 11 is accomplished when reference point 16 passes copier optics 21 for the second time.
Rather than illuminating a document to be copied, illuminating means 25 illuminates photosensitive surface 11 via mirror 28 to further reduce the charge thereon to zero.
BO980-009 ,~ 9~
Under the control of copier controller 18, photosensitive drum 12 continues its counterclockwise rotation and reference point 16 approaches magnetic brush 27 for the second time. In the cleaning portion of the normal copier cycle magnetic brush 27 removes any residual toner from photosensitive surface 11.
After leaving magnetic brush 27 counterclockwise rotation continues until reference point 16 is again under corona 17.
It will be noted from the above description of a normal copier cycle that photosensitive surface 11 undergoes two complete revolutions to produce a xerographic copy. During the copy producing portion of the normal copier cycle, photosensitive surface 11 sequentially passes coronas 17 and 19 for charging, optics 21 for exposing, magnetic brush 27 for developing, and corona 17 for transferring. During the cleaning portion of the normal copier cycle, photosensitive surface 11 sequentially passes corona 19 and optics 21 for charge neutralization, and magnetic brush 27 for toner removal. Reference point 16 is always located at its position under corona 17 as shown in Fig. lj at the beginning and at the end of a normal copier cycle.
While controlling the rotation of photosensitive drum 12, controller 18 also ensures that all copier components are activated at the proper time and for the proper duration, and controls dual mode operation of coronas 17 and 19, optics 21 and magnetic brush 27. Controller 18 may employ analog circuitry, digital logic, a microprocessor or microcomputer to control and synchronize copier operations. In a preferred embodiment of the invention, controller 18 may be a four-bit one-chip microcomputer such as the NEC*~PD546C
available from Nippon Electric Co., Ltd. This one-chip microcomputer includes all the electronic circuitry required for controller 18. Connections between the one-chip microcomputer and the copier components are via interface circuitry provided on the one-chip microcomputer.
As is well known to those skilled in the art, buffers * Trade Mark )~B
..
.... . . .. .
B0980-009 .~ ~7~B~O
-lO-may be employed between the interface circuitry of the one-chip microcomputer and the copier components, to match voltage levels and current requirements of the microcomputer with the individual copier components.
As previously discussed, there are occasions when the normal copier cycle is interrupted. If the normal copier cycle is interrupted, photosensitive drum 12 will be at a rotational position other than the position at the beginning and end of the normal copier cycle shown in Fig. 1. According to the invention, an indicating means is provided for indicating whether or not photosensitive drum 12 is in its rotational position at the beginning or end of a normal copier cycle.
In the embodiment shown in Fig. 1, the indicating means includes timing wheel 36 mounted on shaft 13 for rotation with photosensitive drum 12. The timing wheel has a cam 37 on the periphery thereof. Switch 38 is mounted such that when photosensitive drum 12 is in its rotational position at the end of a normal copier cycle, swi~ch 38 engages cam 37, as shown in Fig. 1. At all rotational positions of photosensitive drum 12 other than at the conclusion of a normal copier cycle, switch 38 will engage the periphery of timing wheel 36 and not engage cam 37~ Therefore, the output of switch 38, represente~ by line 39,will give a first indication when first photosensitive drum 12 is at its position at the end of a normal copier cycle and give a second indication when photosensitive drum 12 is at any other position.
The output of switch 38, represented by line 39, thus forms a basis for inferentially determining the last-powered-on state of the copier. Rather than storing the rotational position of the photosensitive surface in special memory elements as photosensitive drum 12 rotates, and then retaining the last stored position when the copier shuts down, the state of switch 38 need only be determined when power is applied to the copier.
sos~o-oos , .~L1 7 ~9 0 ~ lhen power i5 appliecl to the copier, copier controller 18 determines the state of switch 38. lf switch 38 i5 engaged with cam 37, then it may be inferred that the last-powered-on state of the copier was at the conclusion of a normal copier cycle.
Under the control of controller 18, a normal copier cycle commences without cleaning the photosensitive surface. The sequence of copier operations for a normal copier cycle, including the copy producing portion and cleaning portion has already been described above.
If, on the other hand, switch 38 is not engaged with cam 37, it may be inferred that the last-powered-on state of the copier was at'some state other than lS that at the conclusion of the normal copier cycle.
The actual position of the photosensitive surface is unimportant with regard to copier start-up operations.
Under the control of controller 18, copier start-up operations proceed as follows: The introduction of a document into copier optics 21 is prevented by disabling the rotation of roller pairs 24 and 26.
Under the control of copier controller 18 photosensitive drum 12 begins rotatioh. Copier controller 18 continues to monitor the state of switch 38 until it is determined that switch 38 is engaged with cam 37. The position of reference point 16 will then be as shown in Fig.
1. Under the control of copier controller 18 rotation of photosensitive drum in the counterclockwise direction continues and the cleaning cycle is activated.
Reference point 16 passes coronas 17 and 19. Corona 19 is activated to neutralize the charge on photosen-sitive surface 11. Reference point 16 then passes copier optics 21 which are employed in the cleaning mode to ill~minate photosensitive surface 11 and further neutralize any charge thereon. Rotation continues past magnetic brush 27 which removes any Bo980-oog 13L7~90 residual toner from photoserlsitive surface 11.
Rotation then continues until the copier controller again determines that cam 37 is engaged with switch 38. The position of photosensitive drum 12 is as shown in Fig. 1, and the normal copier cycle may commerlce, utilizing the now cleaned photosensitive surface 11.
The cam and switch combination thus provides a means for inferring the last-powered-on state of the copier. Upon application of power-, if cam 37 engages switch 38, no cleaning is necessary and immediate copying is permitted. If cam 37 does not engage switch 38, the time to first copy will be delayed while the photosensitive surface is cleaned. The delay to first copy equals the time it takes for photosensitive drum 12 to rotate between 1 and 2 complete revolutions. During the first partial revolution, photosensitive drum 12 is rotated until it is ascertained that cam 37 is engaged with switch 38. Photosensitive surface drum 12 then is rotated a full revolution and cleaned.
It will be apparent to those skilled in the art that cam 37 need not be on the peripheral surface of timing wheel 36. It may be on the side of timing wheel 36, provided switch 38 is mounted to engage cam 37 when photosensitive drum 12 is in its position at the conclusion of a normal copier cycle as shown in Fig. 1. Indeed, a separate timing wheel 36 need not be provided at all, as a cam may be formed on the periphery 11 o~ photosensitive drum 12 and switch 3 may be mounted to engage photosensitive drum 12.
It will be apparent to those skilled in the art that the indicatin~ means need not comprise the cam and switch combination described above. Optical indicating means may be provided wherein for example, timing wheel 36 is opaque except for a small transparent portion. Switch 38 would be replaced by a photocell which can distinguish the transparent portion from the remainder of the timing wheel. Alternatively, Bo980-oo9 ~7~90 magnetic indicating means may be provided wherein the timing wheel contains a magnetically sensitive material, e.g., magnetic tape, on the periphery thereof with a magnetic signal at one point. Switch 38 would then be a magnetic head which is responsive to the magnetic signal. As described above with regard to the cam and switch indicating means, a separate timing wheel may be dispensed with and the optical or magnetic data may be impressed directly on drum 12.
Other types of indicating means may be envisioned by those skilled in the art. Regardless of the indicating means provided, the positioning of the indicating means must be such that the output of the indicating means represented'by line 39 gives a first indication when photosensitive drum 12 is in a rotational position at the end of a normal copier cycle and a second indicatlon at all other rotational positions. To provide the required signal amplitude and duration for copier controller 18, the output of switch 38 may be integrated by interposing integrator 41 between switch 38 and copier controller 18 as shown in Fig. 1.
Figure 2 shows a second form of timing wheel with which the invention may be practiced. ~lany xerographic copiers already contain a timing wheel which is used by copier controller 18 for monitoring the position of photosensitive drum 12 during all phases of the normal copier cycle. By monitoring the position of the drum during the copier cycle, controller 18 may activate and deactivate the requisite copier components at the proper time and in the proper sequence.
In keeping with the low cost objective for the copier in which the invention is employed, a second timing wheel is not added to provide copier start-up indicating information. Rather, the already existing timing wheel is employed for a dual purpose, i.e., to supply synchronization information to copier controller 18, as well as to provide copier start-up indicating information.
30~80-009 ~:17~9(~
Synchronization information and copier start-up indicating information is supplied by employing two types of cams on the peripheral surface of timing wheel 46, as shown in Fig. 2. A plurality of small 5 cams 48 are disposed about the periphery of the timing wheel and provide copier synchronization information. The number and position of synchronization cams 48 depend upon the particular design and configuration of the copier, and do not form a part of this invention.
A large indicating cam 47, provides the copier start-up indicating information.
Since timing wheel 46 now has two types of cams on the surface thereof means must be provided for the - copier to distinguish between large indicating cam 47 and the smaller synchronization c~ms 48. A first distinguishing means would provide two switches which engage the periphery of timing wheel 46. The contacting surface of one switch would be large and would only be activated by the large cam 47, i.e., it would pass over small cams 48 without engaging them. This switch would be positioned so that it engaged large cam 47 when the photosensitive surface was in its position at the end of a normal copier cycle shown in Fig. 1. The second switch would have a small con-tacting surface and would contact both small cams 48 and large cam 47 to provide synchronization information.
Alternatively, a second distinguishing means may be provided without requiring the addition of a second switch. The small cams 48 may be distinguished from indicating cam 47 dynamically, i.e., by rotating photosensitive drum 12. Basically, copier controller 18 rechecks the state of switch 38 a short time after it initially determines that switch 38 is engaged with a cam 47 or 48. If at the recheck, switch 38 is still engaged, it is apparent that switch 38 is engaged with large cam 47. I~- switch 38 is no longer engaged, then it is apparent that switch 38 was engaged with a small cam 48 which has disengaged from the switch during the short time interval.
L>o(~o ~()l~ `) -l5-~7;~0 The details of control of copier start-up operations in a copier employing the timing wheel of Fig. 2 will be illustrat.ed with the aid of the flow chart of Fig.
3. As shown in box lQ0, copier controller 18 ascertains that main copier switch 43 has been turned on.
Copier controller 18 prevents the introduction of a document into copier optics 21 by disabling the rotation of roller pairs 24 and 26, and initiates rotation of drum 12 via motor 14, as indicated at 101. Copier controller 18 ascertains the state of switch 38 immediately upon rotation of drum 12, as shown at 102. If switch 38 is in its second state, i.e., it is not engaged with any cam 48 or 47, the copier cont~oller may assume that the last-powered-on state of the copier was at some point other than at the end of the normal copier cycle. Rotation is continued (see 103) until switch 38 appears in its first state (see 104), i.e., it is engaging one of cams 47 or 48. The copier controller must then ascertain if switch 38 is engaging large indicating cam 47 or a small ~ynchronization cam 48. This is done by continuing rotation of photosensitive drum 12 (see 105) and waiting a short time interval and again ascertaining the state of switch 38 (see 106). If at the conclusion of the short time interval switch 38 is still in its first state, it is apparent that switch 38 is engaging the large indicating cam and has therefore remained in its first state for the duration of the short time interval. Since it is now ascertained that cam 47 is engaging switch 38, the position of photosensitive drum 12 is at the position shown in Fig. 1 and the cleaning operation may begin tsee 107). The cleaning portion has been described above with regard to the embodiment of Fig. 1 and will not be described again here. If on the other hand, switch 38 is not in its first state after the duration of a short time interval (see 106~ it is apparent that switch 3g was engaging a small synchroni-zation cam, and rotation of the drum will continue :~7~9(~
until it may be ascertained that switch 38 is engaging the large indicating cam.
If upon initial rotation of the drum (see 1011, switch 38 is not in its second state, i.e., it is engaging one of the cams 47 or 48, copier controller 18 must ascertain if it is engaging large indicating cam 47 or one of the small synchronization cams 48.
Controller 18 continues rotation of the drum and waits a short time interval (see 108). If at the end of the short time interval switch 38 is still in its first state (see 109) it is apparent that switch 38 is engaged with large indicating cam 47. Controller 18 may assume that the copier was shut off at the end of a normal-copier cycle (see 110) and normal copying is enabled (see 111). If at the end of the short time interval, the switch is no lOnger in its first state then it is apparent that the switch was engaging a synchronization cam 48, and that the copier was not shut off at the end of the normal copier cycle. The photosensitive surface must be cleaned, and the copier controller continues rotation of the drum until it is ascertained that the copier is engaged with indicating cam 47, and then initiates the cleaning of photosensitive surface 11.
Other than the dynamic means for distinguishing indicating cam 47 from synchronizing cams 48, control of copier start-up operations is the same as was discussed regarding the embodiment of Fig. 1. When copier controller 18 ascertains that switch 38 was engaged with indicating cam 47, it may be inferred that power was removed at the end of a normal copier cycle. If switch 38 was not engaged with indicating cam 47, i.e., switch 38 was engaged with a small cam 48 or with .the peripheral surface of timing wheel 46, it may be inferred that the copier was interrupted in the middle of a normal copier cycle and photosensitive surface 11 must be cleaned before further copying will be permitted.
A third form of timing wheel with which the invention may be practiced is shown in Fig. 4. In this embodiment, a plurality of individual synchron-1309 8 0 -0 0 9 ~ 3V
-~7-ization cams 58 is provid~d on timing wheel 56. In addition, a pair of closely spaced indicating cams 57 provides copier start-up indicating information. It will be seen from Fig. 4 that cams 58 and 59 are not on the periphery of timing wheel 56 but rather are on the side of timing wheel 56 in a circular pattern thereon. The number and position of synchronization cams 58 in the circular pattern depend upon the particular design and configuration of the copier and do not form a part of this invention. However, for the purpose of explaining the detailed operation of the invention, the number of synchronization cams 58 on timing wheel 56 will be assumed to be four, as shown in Fig. 4. The pair of indicating cams 57 is positioned such that at the conclusion of a normal copier cycle, when photosensitive surface 11 is at its position in Fig. l, switch 38 will engage with timing wheel 56 at point 59.
As with the embodiment of Fig. 2, means must be provided for distinguishing between the indicating cams 57 and the individual synchronizing cams 58. As with the embodiment of Fig. 2, indicating cams 57 may be dynamically distinguished from synchronizing cams 58 by rotating photosensitive drum lO. Basically, copier controller 18 begins rotation of the drum and counts the number of cams engaged by switch 38 until the unique pair of indicating cams is encountered.
If the number of cams engaged equals the number of synchronization cams on the timing wheel then it may be inferred that rotation began with switch 38 engaging timing wheel 56 at point 59, and that the copier was shut off at the conclusion of a normal copier cycle.
If the number of cams engaged does not equal the number of s~nchronization cams on the timing wheel, it may be inferred that rotation began with switch 38 engaging timing wheel 56 at some point other than at 59, as a result of the copier having been interrupted in the middle of a normal copier cycle.
Bo(38o-()Q9 ~7~0 , ~
The details of contr~l of copier star-t-up operations in a copier employing the timing wheel of Fig. 4 will be illustrated through the use of the flow chart of Fig. 5. Copier controller 18 senses the turning on 5 of main copier switch 43, as shown in Fig. 5 at 150.
Copier controller 18 prevents the introduction of a document into copier optics 21 by preventing the rotation of roller pairs 24 and 26, and begins the counterclockwise rotation of drum 12 in order to ascertain the last-powered~on state of the copier.
Copier controller 18 continuously monitors the state of switch 38 via line 39. The changing of the state of switch 38 from its second state to its first state or from its-first state to its second state will 1-5 hereinafter be termed a transition. ~s shown at 152, copier controller 18 counts the number of transitions occurring on line 39 as drum 12 rotates. In addition, the timing between the transitions is monitored. As shown at 153, the controller 18 detects the occurrence of four transitions within a predetermined short time interval. At the conclusion of the fourth of the four closely occurring transitions, switch 38 has just disengaged from the pair of indicating cams 57 and is engaging timing wheel 56 at point 59. PhotosenSitive surface 11 is at its position shown in Fig. 1. The copier controller can infer the last-powered-on state of the copier by observing the number of transitions it has counted prior to switch 38 arriving at point 59.
If the number of transitions is equal to 12, (see 154) the copier controller may infer that at the last-powered-on state of the copier was at the conclusion of the normal copier cycle. The reasoning for this is as follows: At the conclusion of the normal copier cycle, switch 38 is engaged with timing wheel 56 at point 59. When the drum begins its counterclockwise rotation, switch 38 will sequentially engage each of the four synchronization cams 58 and the copier controller will detect a total of 8 transitions ~17~8~30 (i.e., two transitions per cam as switch 38 engages and disengages each synchronization cam 581. Switch 38 will then engage the pair of indicating cams 57 in rapid sequence, and copier controller 18 will detect four closely occurring transitions. Therefore, when the last-powered-on state of the copier was at its position at the end of a normal copier cycle, copier controller 18 will detect a total of 12 transitions from the time it began rotation of the drum until it detects the last of the four closely occurring transitions.
Photosensitive drum 12 has undergoone one complete revolution in order to ascertain that the last-powered-on state was at the end of a normal copier cycle (see 155). At the conclusion of this revolution it is at its position shown in ~ig. 1, i.e., switch 38 engages timing wheel 56 at point 59. Photosensitive surface 12 is in its proper position for beginning a normal copier cycle. Controller 18 begins a normal copier cycle. The normal copier cycle has already been described with regard to Fig. 1 and will not be repeated here.
If the number of transitions counted by copier controller 18 is not equal to 12 (see 1541, copier controller 18 may infer that the copier was interrupted in the middle of a normal copier cycle. The reasoning for this is as follows: If the copier was interrupted in the middle of a normal copying cycle, switch 38 will engage timing wheel 56 at some point other than point 59. When rotation of photosensitive surface 12 begins, it will not sequentially engage all of synchronization cams 58 prior to engaging closely spaced ~indicating cams 57. The number of detected transitions prior to the last of the four closely spaced transitions will therefore not be equal to 12.
This provides the inference for copy controller that the copier was interrupted in the middle of a normal copier cycle (see 156). After detecting the last of the four closely spaced transitions, drum 12 is in its position shown in Fig. 1. Copier con-troller 18 Bo9~0-009 --~ O--initiates cleaning of the photosensitive surface as was described in connection with Fig. 1. At the conclusion of the cleaniny cycle, the position of photosensitive drum 12 will be that shown in Fig. 1 and a normal copier cycle will be enabled (see 157).
It will be seen that when the copier was nterrupted in the middle of a normal copier cycle, photosensitive surface 12 will undergo a fraction of one complete revolution in ord~r to ascertain the last-powered-on state of the copier, and then will undergo a full revolution in order to clean the photosensitive surface.
Many other variations of indicating means, providing static or dynamic indicating information will bë apparent to those skilled in the art. The common inventive concept in all such variations is that the indicating means provides a first indication if the photosensitive surface was in its normal position at the end of the copier cycle when power was removed from the copier and will not provide this indication if the photosensitive surface was in any other position when power was turned off. Means are therefor provided for the copier controller to assume the last-powered-on state of the copier without the need for storing this state in special memory elements.
Whereas we have illustrated and described the various embodiments of our invention it is to be understood that we do not limit outselves to the precise construction herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.
~173~390 Description -CONTROL`OF COPIER START-UP OPERATIONS
Technical Field This invention generally relates to a copier, and more particularly to copier start-up operations control..
It is well known that xerographic copiers include a photosensitive surface which is charged to a uniform potential and then exposed to an image to form a latent electrostatic image. The latent electrostatic image is developed by application of toner thereto. The developed image is transferred to an output medium, generally a - copy paper, and then fixed thereto to produce a permanent copy. Xerographic copiers also include cleaning means employing brushes and/or other means to remove any residual toner left on the photosensitive surface, and neutralize any residual charge left thereon prior to using the photosensitive surface for making a new copy.
In a normal copier cycle, the photosensitive surface,is sequentially moved past a charging station, exposure station, developing station, transfer station and cleaning station. After passing the cleaning station the photosensitive surface i9 returned to its initial position adjacent the charging station, and new copier cycle may begin if further copying is desired. If further copying is not desired, the copier is turned off at the conclusion of the normal copier cycle.
As is well known, the normal copier cycle described above is often interrupted. Power to the copier may be interrupted because of a loss of electrical power due to a power failure or the inadvertent switching off of the main copier switch. More commonly, con-temporary copiers include a protective mechanism which shuts-off the copier upon the occurrence of a paper jam or other abnormal condition during the 7~90 copier cycle. Regardless of whether the copier is shut off under normal eond;tions at the conclusion of a copier cycle, or was interrupted in midstream, means must be provided to control copier start-up upon reappliçation of power. The copier mus-t be available for copy production as quickly as possible upon reapplieation of power, and the initial eopy must be of the same high quality as all subsequent eopies. !i!
A simple control of copier start-up would always elean the photosensitive surfaee upon reapplication of power to ensure that the initial copy is of high quality. Production of copies would be delayed until the photosensitive surface is passed by the cleaning 15 station. It is apparent that this simple start-up control is a waste of time and energy. At the end of a normal copier cycle, the photosensitive surface has already been cleaned, and there is no need to reelean the surfaee when power is reapplied. On the other 20 hand, if copier operation is interrupted in midstream for any of the reasons discussed above, the photo-sensitive surface must be cleaned and prepared before further copying may commence upon reapplication of power.
It is therefore desirable for copier start-up to vary, depending upon the condition upon whieh the eopier previously shut down. If the copier shut down at the end of a normal copieX cyele, eopying may begin immediately upon the reapplieation of power.
30 Time and energy need not be wasted in eleaning an already clean photosensitive surfaee. If, on the other hand, the eopier shut down in the middle of a eopier eycle, eopying may not begin until the photo-sensitive surfaee is cleaned. While the initial 35 eleaning produees a slight delay before produetion of the initial copy, failure to clean the photosensitive surface will result in an initial copy of unacceptable quality.
BO980-009 ~ 9 O
Background A
In the past, large and expensive copiers included special memory elements. These memory elements were relays, mechanical latches, battery powered memory elements or non-volatile read/write memory elements.
When power was removed from the copier, an indication of the point in the copier cycle at which power was removed was stored in the special memory elements. The special memory elements would retain this information while power was removed from the copier. When power was reapplied, copier operations would start up in accordance with the status of the copier prior to power shut-off as specified by the special memory elements. If power was interrupted at the end of a normal copier cycle, copy production would immediately be enabled. If power was interrupted in the middle of a copier cycle, cleaning of the photosensitive surface would take place prior to the production of an initial copy.
Special memory elements, whether mechani_al or electrical, are too expensive and complex to meet the design objectives of a low cost, compact copier. In one form of special memory element, electrical power is maintained at the special memory element even when power is removed from the remainder of the copier. This poses a safety hazard to the copier operator who must open the copier to clear a paper jam, and may receive a shoclc if he touches that part of the copier at which power is still maintained. Other forms of special memory elements employ a battery to retain the information when the copier is shut off. While eliminating any shock hazard, battery powered special memory elements are complex and take up an excess of space in a compact copier. Still vther forms cf special memory elements which do not require electric or battery power are prohibitively expensive for a low cost copier.
In designing a low cost copier, it is desirable to eliminate special memory elements while still controlling copier start-up operations depending upon the last-1iO980-009 .~17~
.~
powered-on state of the co~ier. It is especially desirable to accomplish thi,s control of copier start-up operations through the modification of components already present in the copier. By eliminating special memory elements, the complexity of the copier and the cost thereof may be reduced. By integrating the copier start-up control into preexisting copier components, the benefits of control of copier start-up may be attained with little or no cost increase.
Disclosure of Invention It is an object of the invention to provide improved control of copier start-up operations.
It is another object of the invention to provide control of copier start-up operations without the use of special memory elements for storing the last-powered-on state.
It is another object of the invention to provide control of copier start-up by merely modifyir.g already present copier components.
It is another object of the invention to provide control'of copier start-up which initiates photo-sensitive surface cleaning prior to enabling copy production if the last-powered-on state of the copier was in the middle of a normal copier cycle.
It is still a further object of the invention to provide control of copier start-up which enables immediate copying of a document if the power was removed from the copier after the end of a normal copier cycle.
The,se and other objects are accomplished by providing an indicating means which is responsive to the position of the photosensitive surface. If the photosensitive surface is in its position at the end of a normal copier cycle, i.e., its position after the photosensitive surface has been cleaned, the indicating means provides a first indication. If the photosensitive surface is in any position other than its position at ~0980-009 ~1~'7~
5_ the end of a normal copier cycle, -the indicating means provides a second indication. When power is applied to the copier, the state of the indicating means is ascertained. If the first indicaticn is present, thus signifying that the copier was shut off at the end of a normal copier cycle, immediate copy production is enabled. If the second indication is present, thus signifying the copier was shut off at some point during a copier cycle, production of copies is inhibited and the photosensitive surface is cleaned. Normal copy production is then enabled.
In a first embodiment the photosensitive surface is a drum, and a timing wheel is mounted coaxially with the drum for rotation therewith. The timing wheel has a cam on the periphery thereof. A switch is mounted adjacent the timing wheel to engage the cam when the drum is in its position at the end of a normal copier cycle. The switch provides the first lndication when it engayes the cam and the second indication at all other times.
In a second embodiment a timing wheel is already present in the copier to supply synchronization informatlon for use by the copler controller ln controlllng and synchronizing copy producing operations.
The periphery of the timing wheel has a series of small cams to provide synchronization information.
Copier start-up information is provided by adding a single large indicatlng cam to the already e~lsting timing wheel. Means are also provlded for the copier to distinguish between the large indicating cam and the small synchronization cams.
In a thlrd embodiment the timing wheel is also already present in the copier to supply synchronization inform~tion. The side of the timlng wheel has a series of cams in a circular pattern thereon. Synchron-izatlon informatlon ls provided by individual camsdisplaced at various points in the circular pattern.
Copier start-up indicating information is provided by the addition of a pair of closely spaced cams at a -G-predetermined position in the circular pattern.
~5eans are provided for the copier to distinguish between the individual synchronization cams and the pair of closely spaced indicating cams.
In all embodiments, the indicating cam or cams and switch provide means for controlling copier start-up without the necessity of special memory elements to remember the last-powered-on state of the copier.
Brief Description _ the Drawing Fig. 1 is a schematic representation of a copier having a first embodiment of t,he invention.
- Fig. 2 is a cross sectional view of the timing wheel of a second embodiment of the. invention.
Fig. 3 is a flow char-t representation of the control of copier start-up operations in a copier employing the timing wheel of Fig. 2.
Fig. 4 shown with Fig. 2 is a cross sectional view of the timing wheel of a third embociment of the invention.
Fig. 5 is a flow chart representation of the control of copier start-up operations in a copier employing the timing wheel of Fig. 4.
Best ~50de f Carrying Out the Invention Although the subject invention may be employed in any xerographiG copier, it will be described with respect to a xerographic copier having the configuration of Fig. 1. Xerographic copier 10 generally comprises photosensitive surface 11, here the perhiphery of photosensitive drum 12, mounted on shaft 13 for rotation in the counterclockwise direction by motor 14. Copier 10 is designed to be compact and low cost. To reduce the number of copier components, many of these components are designed to serve a dual purpose in the copying process, as will be described below.
A normal copier cycle will now be described.
Reference point 16 will be employed for the purposes _ _ ~0~80-009 ~ ~73~o of describing the rotation of the photosensitive drum 12 past the copier components. It will be understood that reference point 16 is not actually present on photosensitive drum. For the purposes of illustrating a normal copier cycle, it will also be assumed that the copier was turned off at the conclusion of a previous normal copying cycle. When this is the case, photosensitive drum 12 will always be at its position shown in Fig. 1, i.e., reference point 16 10 will be adjacent corona 17.
To begin the normal copier cycle copier controller 18 initiates rotation of drum 12 in the counterclock-wise direction by activating motor 14. Reference point 16 passes corona 17. Corona 17, under the 15 control of copier controller 18, charges photosensitive surface 11 to a very high negative voltage. Rotation continues and reference point 16 passes corona 19.
Under the control of copier controller 18, corona 19 smooths the charge on photosensitive surface 11 so 20 that it is uniform throughout the photosensitive surface.
Photosensitive drum 12 continues to rotate until reference point 16 approaches copier optics 21.
Copier optics assembly 21 is represented schemmatically 25 by optic element 22, which may be a fiber optics bundle, for examp]e. Copier optics assembly further includes document glass 23, illumination means 25, mirror 28 and roller pairs 24 and 26. When reference point 16 approaches fiber optics element 22, copier 30 controller 18 activates roller pairs 24 and 26 to move the document to be copied across document glass 23 from Eoller pair 24 to roller pair 26, at the same speed as the peripheral speed of photosensitive surface 11. Illumination means 25 is turned on and 35 optic element 22 scans the document to be copied and forms a latent electrostatic image on the photo-sensitive surface 11.
Bo98o-oo9 ~1 7~
Continuing its counterclockwise rotation, reference point 16 approaches magnetic brush 27. Under the control of controller 18, magnetic brush 27 develops the latent electrostatic image by applying toner to the charged portions of the photosensitive surface.
Rotation of the drum continues and reference point 16 approaches corona 17 for the second time. As reference point 16 approaches corona 17, copier controller 18 causes a sheet of copy paper to be picked from paper supply 29 and to travel along paper path 31. The copy paper sheet and reference point 16 approach corona 17 simultaneously, at the same linear speed.
Corona 17 which was previously employed as part - of the charging station now acts as a transfer station Corona 17 transfers the toner from the surface 11 of photosensitive drum 12 to the copy paper. The copy paper continues along paper path 32 and encounters fuser station 33, here represented by fuser roller pair.34 Through a combination of heat and/or pressure, rollers 34 permanently fuse the toner to the copy paper.
The sequence of operations described above, beginning with reference point 16 passing corona 17 for the first time and ending after point 16 has passed corona 17 for the second time constitute the copy producing portion of a normal copier cycle.
Rotation of photosensitive drum 12 continues and reference point 16 approaches corona 19 for the second time. This is the beginning of the cleaning portion of a normal copier cycle. Corona 19 is now employed to remove any residual charge left on photo-sensitive surface 11. Further discharging of photo-sensitive surface 11 is accomplished when reference point 16 passes copier optics 21 for the second time.
Rather than illuminating a document to be copied, illuminating means 25 illuminates photosensitive surface 11 via mirror 28 to further reduce the charge thereon to zero.
BO980-009 ,~ 9~
Under the control of copier controller 18, photosensitive drum 12 continues its counterclockwise rotation and reference point 16 approaches magnetic brush 27 for the second time. In the cleaning portion of the normal copier cycle magnetic brush 27 removes any residual toner from photosensitive surface 11.
After leaving magnetic brush 27 counterclockwise rotation continues until reference point 16 is again under corona 17.
It will be noted from the above description of a normal copier cycle that photosensitive surface 11 undergoes two complete revolutions to produce a xerographic copy. During the copy producing portion of the normal copier cycle, photosensitive surface 11 sequentially passes coronas 17 and 19 for charging, optics 21 for exposing, magnetic brush 27 for developing, and corona 17 for transferring. During the cleaning portion of the normal copier cycle, photosensitive surface 11 sequentially passes corona 19 and optics 21 for charge neutralization, and magnetic brush 27 for toner removal. Reference point 16 is always located at its position under corona 17 as shown in Fig. lj at the beginning and at the end of a normal copier cycle.
While controlling the rotation of photosensitive drum 12, controller 18 also ensures that all copier components are activated at the proper time and for the proper duration, and controls dual mode operation of coronas 17 and 19, optics 21 and magnetic brush 27. Controller 18 may employ analog circuitry, digital logic, a microprocessor or microcomputer to control and synchronize copier operations. In a preferred embodiment of the invention, controller 18 may be a four-bit one-chip microcomputer such as the NEC*~PD546C
available from Nippon Electric Co., Ltd. This one-chip microcomputer includes all the electronic circuitry required for controller 18. Connections between the one-chip microcomputer and the copier components are via interface circuitry provided on the one-chip microcomputer.
As is well known to those skilled in the art, buffers * Trade Mark )~B
..
.... . . .. .
B0980-009 .~ ~7~B~O
-lO-may be employed between the interface circuitry of the one-chip microcomputer and the copier components, to match voltage levels and current requirements of the microcomputer with the individual copier components.
As previously discussed, there are occasions when the normal copier cycle is interrupted. If the normal copier cycle is interrupted, photosensitive drum 12 will be at a rotational position other than the position at the beginning and end of the normal copier cycle shown in Fig. 1. According to the invention, an indicating means is provided for indicating whether or not photosensitive drum 12 is in its rotational position at the beginning or end of a normal copier cycle.
In the embodiment shown in Fig. 1, the indicating means includes timing wheel 36 mounted on shaft 13 for rotation with photosensitive drum 12. The timing wheel has a cam 37 on the periphery thereof. Switch 38 is mounted such that when photosensitive drum 12 is in its rotational position at the end of a normal copier cycle, swi~ch 38 engages cam 37, as shown in Fig. 1. At all rotational positions of photosensitive drum 12 other than at the conclusion of a normal copier cycle, switch 38 will engage the periphery of timing wheel 36 and not engage cam 37~ Therefore, the output of switch 38, represente~ by line 39,will give a first indication when first photosensitive drum 12 is at its position at the end of a normal copier cycle and give a second indication when photosensitive drum 12 is at any other position.
The output of switch 38, represented by line 39, thus forms a basis for inferentially determining the last-powered-on state of the copier. Rather than storing the rotational position of the photosensitive surface in special memory elements as photosensitive drum 12 rotates, and then retaining the last stored position when the copier shuts down, the state of switch 38 need only be determined when power is applied to the copier.
sos~o-oos , .~L1 7 ~9 0 ~ lhen power i5 appliecl to the copier, copier controller 18 determines the state of switch 38. lf switch 38 i5 engaged with cam 37, then it may be inferred that the last-powered-on state of the copier was at the conclusion of a normal copier cycle.
Under the control of controller 18, a normal copier cycle commences without cleaning the photosensitive surface. The sequence of copier operations for a normal copier cycle, including the copy producing portion and cleaning portion has already been described above.
If, on the other hand, switch 38 is not engaged with cam 37, it may be inferred that the last-powered-on state of the copier was at'some state other than lS that at the conclusion of the normal copier cycle.
The actual position of the photosensitive surface is unimportant with regard to copier start-up operations.
Under the control of controller 18, copier start-up operations proceed as follows: The introduction of a document into copier optics 21 is prevented by disabling the rotation of roller pairs 24 and 26.
Under the control of copier controller 18 photosensitive drum 12 begins rotatioh. Copier controller 18 continues to monitor the state of switch 38 until it is determined that switch 38 is engaged with cam 37. The position of reference point 16 will then be as shown in Fig.
1. Under the control of copier controller 18 rotation of photosensitive drum in the counterclockwise direction continues and the cleaning cycle is activated.
Reference point 16 passes coronas 17 and 19. Corona 19 is activated to neutralize the charge on photosen-sitive surface 11. Reference point 16 then passes copier optics 21 which are employed in the cleaning mode to ill~minate photosensitive surface 11 and further neutralize any charge thereon. Rotation continues past magnetic brush 27 which removes any Bo980-oog 13L7~90 residual toner from photoserlsitive surface 11.
Rotation then continues until the copier controller again determines that cam 37 is engaged with switch 38. The position of photosensitive drum 12 is as shown in Fig. 1, and the normal copier cycle may commerlce, utilizing the now cleaned photosensitive surface 11.
The cam and switch combination thus provides a means for inferring the last-powered-on state of the copier. Upon application of power-, if cam 37 engages switch 38, no cleaning is necessary and immediate copying is permitted. If cam 37 does not engage switch 38, the time to first copy will be delayed while the photosensitive surface is cleaned. The delay to first copy equals the time it takes for photosensitive drum 12 to rotate between 1 and 2 complete revolutions. During the first partial revolution, photosensitive drum 12 is rotated until it is ascertained that cam 37 is engaged with switch 38. Photosensitive surface drum 12 then is rotated a full revolution and cleaned.
It will be apparent to those skilled in the art that cam 37 need not be on the peripheral surface of timing wheel 36. It may be on the side of timing wheel 36, provided switch 38 is mounted to engage cam 37 when photosensitive drum 12 is in its position at the conclusion of a normal copier cycle as shown in Fig. 1. Indeed, a separate timing wheel 36 need not be provided at all, as a cam may be formed on the periphery 11 o~ photosensitive drum 12 and switch 3 may be mounted to engage photosensitive drum 12.
It will be apparent to those skilled in the art that the indicatin~ means need not comprise the cam and switch combination described above. Optical indicating means may be provided wherein for example, timing wheel 36 is opaque except for a small transparent portion. Switch 38 would be replaced by a photocell which can distinguish the transparent portion from the remainder of the timing wheel. Alternatively, Bo980-oo9 ~7~90 magnetic indicating means may be provided wherein the timing wheel contains a magnetically sensitive material, e.g., magnetic tape, on the periphery thereof with a magnetic signal at one point. Switch 38 would then be a magnetic head which is responsive to the magnetic signal. As described above with regard to the cam and switch indicating means, a separate timing wheel may be dispensed with and the optical or magnetic data may be impressed directly on drum 12.
Other types of indicating means may be envisioned by those skilled in the art. Regardless of the indicating means provided, the positioning of the indicating means must be such that the output of the indicating means represented'by line 39 gives a first indication when photosensitive drum 12 is in a rotational position at the end of a normal copier cycle and a second indicatlon at all other rotational positions. To provide the required signal amplitude and duration for copier controller 18, the output of switch 38 may be integrated by interposing integrator 41 between switch 38 and copier controller 18 as shown in Fig. 1.
Figure 2 shows a second form of timing wheel with which the invention may be practiced. ~lany xerographic copiers already contain a timing wheel which is used by copier controller 18 for monitoring the position of photosensitive drum 12 during all phases of the normal copier cycle. By monitoring the position of the drum during the copier cycle, controller 18 may activate and deactivate the requisite copier components at the proper time and in the proper sequence.
In keeping with the low cost objective for the copier in which the invention is employed, a second timing wheel is not added to provide copier start-up indicating information. Rather, the already existing timing wheel is employed for a dual purpose, i.e., to supply synchronization information to copier controller 18, as well as to provide copier start-up indicating information.
30~80-009 ~:17~9(~
Synchronization information and copier start-up indicating information is supplied by employing two types of cams on the peripheral surface of timing wheel 46, as shown in Fig. 2. A plurality of small 5 cams 48 are disposed about the periphery of the timing wheel and provide copier synchronization information. The number and position of synchronization cams 48 depend upon the particular design and configuration of the copier, and do not form a part of this invention.
A large indicating cam 47, provides the copier start-up indicating information.
Since timing wheel 46 now has two types of cams on the surface thereof means must be provided for the - copier to distinguish between large indicating cam 47 and the smaller synchronization c~ms 48. A first distinguishing means would provide two switches which engage the periphery of timing wheel 46. The contacting surface of one switch would be large and would only be activated by the large cam 47, i.e., it would pass over small cams 48 without engaging them. This switch would be positioned so that it engaged large cam 47 when the photosensitive surface was in its position at the end of a normal copier cycle shown in Fig. 1. The second switch would have a small con-tacting surface and would contact both small cams 48 and large cam 47 to provide synchronization information.
Alternatively, a second distinguishing means may be provided without requiring the addition of a second switch. The small cams 48 may be distinguished from indicating cam 47 dynamically, i.e., by rotating photosensitive drum 12. Basically, copier controller 18 rechecks the state of switch 38 a short time after it initially determines that switch 38 is engaged with a cam 47 or 48. If at the recheck, switch 38 is still engaged, it is apparent that switch 38 is engaged with large cam 47. I~- switch 38 is no longer engaged, then it is apparent that switch 38 was engaged with a small cam 48 which has disengaged from the switch during the short time interval.
L>o(~o ~()l~ `) -l5-~7;~0 The details of control of copier start-up operations in a copier employing the timing wheel of Fig. 2 will be illustrat.ed with the aid of the flow chart of Fig.
3. As shown in box lQ0, copier controller 18 ascertains that main copier switch 43 has been turned on.
Copier controller 18 prevents the introduction of a document into copier optics 21 by disabling the rotation of roller pairs 24 and 26, and initiates rotation of drum 12 via motor 14, as indicated at 101. Copier controller 18 ascertains the state of switch 38 immediately upon rotation of drum 12, as shown at 102. If switch 38 is in its second state, i.e., it is not engaged with any cam 48 or 47, the copier cont~oller may assume that the last-powered-on state of the copier was at some point other than at the end of the normal copier cycle. Rotation is continued (see 103) until switch 38 appears in its first state (see 104), i.e., it is engaging one of cams 47 or 48. The copier controller must then ascertain if switch 38 is engaging large indicating cam 47 or a small ~ynchronization cam 48. This is done by continuing rotation of photosensitive drum 12 (see 105) and waiting a short time interval and again ascertaining the state of switch 38 (see 106). If at the conclusion of the short time interval switch 38 is still in its first state, it is apparent that switch 38 is engaging the large indicating cam and has therefore remained in its first state for the duration of the short time interval. Since it is now ascertained that cam 47 is engaging switch 38, the position of photosensitive drum 12 is at the position shown in Fig. 1 and the cleaning operation may begin tsee 107). The cleaning portion has been described above with regard to the embodiment of Fig. 1 and will not be described again here. If on the other hand, switch 38 is not in its first state after the duration of a short time interval (see 106~ it is apparent that switch 3g was engaging a small synchroni-zation cam, and rotation of the drum will continue :~7~9(~
until it may be ascertained that switch 38 is engaging the large indicating cam.
If upon initial rotation of the drum (see 1011, switch 38 is not in its second state, i.e., it is engaging one of the cams 47 or 48, copier controller 18 must ascertain if it is engaging large indicating cam 47 or one of the small synchronization cams 48.
Controller 18 continues rotation of the drum and waits a short time interval (see 108). If at the end of the short time interval switch 38 is still in its first state (see 109) it is apparent that switch 38 is engaged with large indicating cam 47. Controller 18 may assume that the copier was shut off at the end of a normal-copier cycle (see 110) and normal copying is enabled (see 111). If at the end of the short time interval, the switch is no lOnger in its first state then it is apparent that the switch was engaging a synchronization cam 48, and that the copier was not shut off at the end of the normal copier cycle. The photosensitive surface must be cleaned, and the copier controller continues rotation of the drum until it is ascertained that the copier is engaged with indicating cam 47, and then initiates the cleaning of photosensitive surface 11.
Other than the dynamic means for distinguishing indicating cam 47 from synchronizing cams 48, control of copier start-up operations is the same as was discussed regarding the embodiment of Fig. 1. When copier controller 18 ascertains that switch 38 was engaged with indicating cam 47, it may be inferred that power was removed at the end of a normal copier cycle. If switch 38 was not engaged with indicating cam 47, i.e., switch 38 was engaged with a small cam 48 or with .the peripheral surface of timing wheel 46, it may be inferred that the copier was interrupted in the middle of a normal copier cycle and photosensitive surface 11 must be cleaned before further copying will be permitted.
A third form of timing wheel with which the invention may be practiced is shown in Fig. 4. In this embodiment, a plurality of individual synchron-1309 8 0 -0 0 9 ~ 3V
-~7-ization cams 58 is provid~d on timing wheel 56. In addition, a pair of closely spaced indicating cams 57 provides copier start-up indicating information. It will be seen from Fig. 4 that cams 58 and 59 are not on the periphery of timing wheel 56 but rather are on the side of timing wheel 56 in a circular pattern thereon. The number and position of synchronization cams 58 in the circular pattern depend upon the particular design and configuration of the copier and do not form a part of this invention. However, for the purpose of explaining the detailed operation of the invention, the number of synchronization cams 58 on timing wheel 56 will be assumed to be four, as shown in Fig. 4. The pair of indicating cams 57 is positioned such that at the conclusion of a normal copier cycle, when photosensitive surface 11 is at its position in Fig. l, switch 38 will engage with timing wheel 56 at point 59.
As with the embodiment of Fig. 2, means must be provided for distinguishing between the indicating cams 57 and the individual synchronizing cams 58. As with the embodiment of Fig. 2, indicating cams 57 may be dynamically distinguished from synchronizing cams 58 by rotating photosensitive drum lO. Basically, copier controller 18 begins rotation of the drum and counts the number of cams engaged by switch 38 until the unique pair of indicating cams is encountered.
If the number of cams engaged equals the number of synchronization cams on the timing wheel then it may be inferred that rotation began with switch 38 engaging timing wheel 56 at point 59, and that the copier was shut off at the conclusion of a normal copier cycle.
If the number of cams engaged does not equal the number of s~nchronization cams on the timing wheel, it may be inferred that rotation began with switch 38 engaging timing wheel 56 at some point other than at 59, as a result of the copier having been interrupted in the middle of a normal copier cycle.
Bo(38o-()Q9 ~7~0 , ~
The details of contr~l of copier star-t-up operations in a copier employing the timing wheel of Fig. 4 will be illustrated through the use of the flow chart of Fig. 5. Copier controller 18 senses the turning on 5 of main copier switch 43, as shown in Fig. 5 at 150.
Copier controller 18 prevents the introduction of a document into copier optics 21 by preventing the rotation of roller pairs 24 and 26, and begins the counterclockwise rotation of drum 12 in order to ascertain the last-powered~on state of the copier.
Copier controller 18 continuously monitors the state of switch 38 via line 39. The changing of the state of switch 38 from its second state to its first state or from its-first state to its second state will 1-5 hereinafter be termed a transition. ~s shown at 152, copier controller 18 counts the number of transitions occurring on line 39 as drum 12 rotates. In addition, the timing between the transitions is monitored. As shown at 153, the controller 18 detects the occurrence of four transitions within a predetermined short time interval. At the conclusion of the fourth of the four closely occurring transitions, switch 38 has just disengaged from the pair of indicating cams 57 and is engaging timing wheel 56 at point 59. PhotosenSitive surface 11 is at its position shown in Fig. 1. The copier controller can infer the last-powered-on state of the copier by observing the number of transitions it has counted prior to switch 38 arriving at point 59.
If the number of transitions is equal to 12, (see 154) the copier controller may infer that at the last-powered-on state of the copier was at the conclusion of the normal copier cycle. The reasoning for this is as follows: At the conclusion of the normal copier cycle, switch 38 is engaged with timing wheel 56 at point 59. When the drum begins its counterclockwise rotation, switch 38 will sequentially engage each of the four synchronization cams 58 and the copier controller will detect a total of 8 transitions ~17~8~30 (i.e., two transitions per cam as switch 38 engages and disengages each synchronization cam 581. Switch 38 will then engage the pair of indicating cams 57 in rapid sequence, and copier controller 18 will detect four closely occurring transitions. Therefore, when the last-powered-on state of the copier was at its position at the end of a normal copier cycle, copier controller 18 will detect a total of 12 transitions from the time it began rotation of the drum until it detects the last of the four closely occurring transitions.
Photosensitive drum 12 has undergoone one complete revolution in order to ascertain that the last-powered-on state was at the end of a normal copier cycle (see 155). At the conclusion of this revolution it is at its position shown in ~ig. 1, i.e., switch 38 engages timing wheel 56 at point 59. Photosensitive surface 12 is in its proper position for beginning a normal copier cycle. Controller 18 begins a normal copier cycle. The normal copier cycle has already been described with regard to Fig. 1 and will not be repeated here.
If the number of transitions counted by copier controller 18 is not equal to 12 (see 1541, copier controller 18 may infer that the copier was interrupted in the middle of a normal copier cycle. The reasoning for this is as follows: If the copier was interrupted in the middle of a normal copying cycle, switch 38 will engage timing wheel 56 at some point other than point 59. When rotation of photosensitive surface 12 begins, it will not sequentially engage all of synchronization cams 58 prior to engaging closely spaced ~indicating cams 57. The number of detected transitions prior to the last of the four closely spaced transitions will therefore not be equal to 12.
This provides the inference for copy controller that the copier was interrupted in the middle of a normal copier cycle (see 156). After detecting the last of the four closely spaced transitions, drum 12 is in its position shown in Fig. 1. Copier con-troller 18 Bo9~0-009 --~ O--initiates cleaning of the photosensitive surface as was described in connection with Fig. 1. At the conclusion of the cleaniny cycle, the position of photosensitive drum 12 will be that shown in Fig. 1 and a normal copier cycle will be enabled (see 157).
It will be seen that when the copier was nterrupted in the middle of a normal copier cycle, photosensitive surface 12 will undergo a fraction of one complete revolution in ord~r to ascertain the last-powered-on state of the copier, and then will undergo a full revolution in order to clean the photosensitive surface.
Many other variations of indicating means, providing static or dynamic indicating information will bë apparent to those skilled in the art. The common inventive concept in all such variations is that the indicating means provides a first indication if the photosensitive surface was in its normal position at the end of the copier cycle when power was removed from the copier and will not provide this indication if the photosensitive surface was in any other position when power was turned off. Means are therefor provided for the copier controller to assume the last-powered-on state of the copier without the need for storing this state in special memory elements.
Whereas we have illustrated and described the various embodiments of our invention it is to be understood that we do not limit outselves to the precise construction herein disclosed and the right is reserved to all changes and modifications coming within the scope of the invention as defined in the appended claims.
Claims (31)
1. A copier comprising:
copy producing means including a movable photosen-sitive surface;
cleaning means for preparing said photosensitive surface for image recording use; and a start-up controller connected to said copy producing means and said cleaning means, responsive to the position of said photosensitive surface upon application of power to said copier, for first activating said copy producing means and subsequently activating said cleaning means consequent upon said photosensitive surface being in a predetermined position, and for first activating said cleaning means and subsequently activating said copy producing means consequent upon said photosensitive surface being in a position other than the aforesaid predetermined position.
copy producing means including a movable photosen-sitive surface;
cleaning means for preparing said photosensitive surface for image recording use; and a start-up controller connected to said copy producing means and said cleaning means, responsive to the position of said photosensitive surface upon application of power to said copier, for first activating said copy producing means and subsequently activating said cleaning means consequent upon said photosensitive surface being in a predetermined position, and for first activating said cleaning means and subsequently activating said copy producing means consequent upon said photosensitive surface being in a position other than the aforesaid predetermined position.
2. In a copier having a copying mode wherein a latent electrostatic image is formed on a movable photosensitive surface, and the latent electrostatic image is fixed and developed, and having a cleaning mode for cleaning said photosensitive surface, apparatus for controlling the start-up of said copier, comprising:
means for detecting if said photosensitive surface is at a predetermined position upon the start-up of said copier, first means responsive to said detecting means for enabling said copying mode consequent upon said photosensitive surface being in the aforesaid predetermined position; and second means responsive to said detecting means for activating said cleaning mode consequent upon said photosensitive surface being in a position other than the aforesaid predetermined position.
means for detecting if said photosensitive surface is at a predetermined position upon the start-up of said copier, first means responsive to said detecting means for enabling said copying mode consequent upon said photosensitive surface being in the aforesaid predetermined position; and second means responsive to said detecting means for activating said cleaning mode consequent upon said photosensitive surface being in a position other than the aforesaid predetermined position.
3. The copier of claim 2 wherein said first means further includes means for activating said cleaning mode upon the conclusion of said copying mode.
4. The copier of claim 2 wherein said second means further includes means for enabling said copying mode upon the conclusion of said cleaning mode.
5. A copier comprising:
a movable photosensitive surface;
charging means for applying a uniform electrical potential to said photosensitive surface;
exposure means for forming a latent electrostatic image on said photosensitive surface;
developing means for transforming the latent electrostatic image into a visible image;
transferring means for shifting at least a portion of the visible image to an output media;
fixing means for rendering the visible image permanent on the output media;
cleaning means for preparing said photosensitive surface for image recording use;
indicating means, responsive to the position of said photosensitive surface, for producing a first indication if said photosensitive surface is located at a predetermined position and for producing a second indication if said photo-sensitive surface is located at any position other than the aforesaid predetermined position;
power sensing means for sensing the application of electrical power to said copier; and first means connected to said cleaning means, said indicating means, and said power sensing means; responsive to the presence of said second indication, for activating said cleaning means when power is applied to said copier and said photosensitive surface is located at any position other than the aforesaid predetermined position.
a movable photosensitive surface;
charging means for applying a uniform electrical potential to said photosensitive surface;
exposure means for forming a latent electrostatic image on said photosensitive surface;
developing means for transforming the latent electrostatic image into a visible image;
transferring means for shifting at least a portion of the visible image to an output media;
fixing means for rendering the visible image permanent on the output media;
cleaning means for preparing said photosensitive surface for image recording use;
indicating means, responsive to the position of said photosensitive surface, for producing a first indication if said photosensitive surface is located at a predetermined position and for producing a second indication if said photo-sensitive surface is located at any position other than the aforesaid predetermined position;
power sensing means for sensing the application of electrical power to said copier; and first means connected to said cleaning means, said indicating means, and said power sensing means; responsive to the presence of said second indication, for activating said cleaning means when power is applied to said copier and said photosensitive surface is located at any position other than the aforesaid predetermined position.
6. The copier of claim 5 further including second means connected to said charging means, said exposure means, said developing means, said transferring means, said fixing means, said indicating means and said power sensing means, responsive to the presence of said second indication for disabling said exposure means, said developing means, said transferring means and said fixing means when power is applied to said copier and said photosensitive surface is at any position other than the aforesaid predetermined position.
7. A copier comprising:
a movable photosensitive surface;
charging means for applying a uniform electrical potential to said photosensitive surface;
exposure means for forming a latent electrostatic image on said photosensitive surface;
developing means for transforming the latent electrostatic image into a visible image;
transferring means for shifting at least a portion of the visible image to an output media;
fixing means for rendering the visible image permanent on the output media;
cleaning means for preparing said photosensitive surface for image recording use;
indicating means, responsive to the position of said photosensitive surface, for producing a first indication if said photosensitive surface is located at a predetermined position and for producing a second indication if said photosensi-tive surface is located at any position other than the aforesaid predetermined position;
power sensing means for sensing the application of electrical power to said copier; and first means connected to said charging means, said exposure means, said developing means, said transferring means, said cleaning means, said indicating means and said power sensing means, responsive to the presence of said first indication, for sequentially activating said exposure means, said developing means, said transferring means and said cleaning means when power is applied to said copier and said photosensitive surface is in said predetermined position.
a movable photosensitive surface;
charging means for applying a uniform electrical potential to said photosensitive surface;
exposure means for forming a latent electrostatic image on said photosensitive surface;
developing means for transforming the latent electrostatic image into a visible image;
transferring means for shifting at least a portion of the visible image to an output media;
fixing means for rendering the visible image permanent on the output media;
cleaning means for preparing said photosensitive surface for image recording use;
indicating means, responsive to the position of said photosensitive surface, for producing a first indication if said photosensitive surface is located at a predetermined position and for producing a second indication if said photosensi-tive surface is located at any position other than the aforesaid predetermined position;
power sensing means for sensing the application of electrical power to said copier; and first means connected to said charging means, said exposure means, said developing means, said transferring means, said cleaning means, said indicating means and said power sensing means, responsive to the presence of said first indication, for sequentially activating said exposure means, said developing means, said transferring means and said cleaning means when power is applied to said copier and said photosensitive surface is in said predetermined position.
8. A copier comprising:
copy producing means including a movable photosen-sitive surface;
cleaning means for preparing said photosensitive surface for image recording use;
indicating means, responsive to the position of said photosensitive surface upon application of power to said copier, for producing a first indication if said photosensitive surface is at a predetermined position and for producing a second indication if said photosensitive surface is at a position other than the aforesaid pre-determined position; and first means connected to said cleaning means and said indicating means, responsive to the presence of said second indication, for activating said cleaning means when power is applied to said copier and said photosensitive surface is at a position other than the aforesaid predetermined position.
copy producing means including a movable photosen-sitive surface;
cleaning means for preparing said photosensitive surface for image recording use;
indicating means, responsive to the position of said photosensitive surface upon application of power to said copier, for producing a first indication if said photosensitive surface is at a predetermined position and for producing a second indication if said photosensitive surface is at a position other than the aforesaid pre-determined position; and first means connected to said cleaning means and said indicating means, responsive to the presence of said second indication, for activating said cleaning means when power is applied to said copier and said photosensitive surface is at a position other than the aforesaid predetermined position.
9. The copier of claim 8 further including second means connected to said copy producing means, and said indicating means responsive to the presence of said second indication for disabling said copy producing means when power is applied to said copier and said photosensitive surface is at a position other than the aforesaid predetermined position.
10. The copier of claim 5, 7 or 8 wherein said indlcating means comprises:
a timlng wheel coupled to said photosensitive surface, said timing wheel having an indicating cam on the surface thereof; and a switch mounted adjacent said timing wheel for engaging said indicating cam when said photosensitive surface is at said predetermined position to thereby provide said first indication, and for engaging the surface of said timing wheel when said photosensitive surface is at any position other than said predetermined position, to thereby provide said second indication.
a timlng wheel coupled to said photosensitive surface, said timing wheel having an indicating cam on the surface thereof; and a switch mounted adjacent said timing wheel for engaging said indicating cam when said photosensitive surface is at said predetermined position to thereby provide said first indication, and for engaging the surface of said timing wheel when said photosensitive surface is at any position other than said predetermined position, to thereby provide said second indication.
11. The copier of claim 5, 7 or 8 wherein said indicating means comprises:
a timing wheel coupled to sai.d photosensitive surface, said timing wheel having an indicating cam on the surface thereof;
a switch mounted adjacent said timing wheel for engaging said indicating cam when said photosensitive surface is at said predetermined position to thereby provide said first indication, and for engaginy the surface of said timing wheel when said photosensitlve surface is at any position other than said predetermined position, to thereby provide said second indication;
said timing wheel further includes a synchronization cam on the surface thereof for engaging said switch, and wherein said indicating rneans further includes means for distinguishing between the engagement of said switch with said indicating cam and with said synchronization cam to provide said first indication when said switch engages said indicating cam and said second indication when said switch engages said synchronization cam.
a timing wheel coupled to sai.d photosensitive surface, said timing wheel having an indicating cam on the surface thereof;
a switch mounted adjacent said timing wheel for engaging said indicating cam when said photosensitive surface is at said predetermined position to thereby provide said first indication, and for engaginy the surface of said timing wheel when said photosensitlve surface is at any position other than said predetermined position, to thereby provide said second indication;
said timing wheel further includes a synchronization cam on the surface thereof for engaging said switch, and wherein said indicating rneans further includes means for distinguishing between the engagement of said switch with said indicating cam and with said synchronization cam to provide said first indication when said switch engages said indicating cam and said second indication when said switch engages said synchronization cam.
12. The copier of claim 5, 7 or 8 wherein said indicating means comprises:
a timing wheel coupled to said photosensitive surface, said timing wheel having a pair of closely spaced indicating cams on the surface thereof; and a switch mounted adjacent said timing wheel for engaging the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams when said photosensitive surface is at said predetermined position to thereby provide said first indication and for engaging the remainder of the surface of said timing wheel when said photosensitive surface is at any position other than said predetermined position, to thereby provide said second indication.
a timing wheel coupled to said photosensitive surface, said timing wheel having a pair of closely spaced indicating cams on the surface thereof; and a switch mounted adjacent said timing wheel for engaging the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams when said photosensitive surface is at said predetermined position to thereby provide said first indication and for engaging the remainder of the surface of said timing wheel when said photosensitive surface is at any position other than said predetermined position, to thereby provide said second indication.
13. The copier of claims 5, 7 or 8 wherein said indicating means comprises:
a timing wheel coupled to said photosensitive surface, said timing wheel having a pair of closely spaced indicating cams on the surface thereof; and a switch mounted adjacent said timing wheel for engaging the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams when said photosensitive surface is at said predetermined position to thereby provide said first indication and for engaging the remainder of the surface of said timing wheel when said photosensitive surface is at any position other than said predetermined position, to thereby provide said second indication;
wherein said timing wheel further includes a synchronization cam on the surface thereof for engaging said switch; and wherein said indicating means further includes means for distinguishing between the engagement of said switch with the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams and with said synchronization cam to provide said first indication when said switch engages the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams and said second indication when said switch engages said synchronization cam.
a timing wheel coupled to said photosensitive surface, said timing wheel having a pair of closely spaced indicating cams on the surface thereof; and a switch mounted adjacent said timing wheel for engaging the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams when said photosensitive surface is at said predetermined position to thereby provide said first indication and for engaging the remainder of the surface of said timing wheel when said photosensitive surface is at any position other than said predetermined position, to thereby provide said second indication;
wherein said timing wheel further includes a synchronization cam on the surface thereof for engaging said switch; and wherein said indicating means further includes means for distinguishing between the engagement of said switch with the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams and with said synchronization cam to provide said first indication when said switch engages the surface of said timing wheel in close proximity to said pair of closely spaced indicating cams and said second indication when said switch engages said synchronization cam.
14. The copier of claim 5, 7 or 8 wherein said indicating means comprises:
a timing wheel coupled to said photosensitive surface, having an optical signal on one portion thereof; and an optical detector mounted adjacent said timing wheel for detecting said optical signal when said photosensitive surface is at said predetermined position to thereby provide said first indication, and for detecting the absence of said optical BO980-0??
signal when said photosensitive surface is at any position other than said predetermined position to thereby provide said second indication.
a timing wheel coupled to said photosensitive surface, having an optical signal on one portion thereof; and an optical detector mounted adjacent said timing wheel for detecting said optical signal when said photosensitive surface is at said predetermined position to thereby provide said first indication, and for detecting the absence of said optical BO980-0??
signal when said photosensitive surface is at any position other than said predetermined position to thereby provide said second indication.
15. The copier of claim 5, 7 or 8 wherein said indicating means comprises:
a timing wheel coupled to said photosensitive surface having a magnetic signal on one portion thereof; and a magnetic signal detector mounted adjacent said timing wheel for detecting said magnetic signal when said photosensitive surface is at said predetermined position, to provide said first indication, and for detecting the absence of said magnetic signal when said photosensitive surface is at any position other than said predetermined position to provide said second indication.
a timing wheel coupled to said photosensitive surface having a magnetic signal on one portion thereof; and a magnetic signal detector mounted adjacent said timing wheel for detecting said magnetic signal when said photosensitive surface is at said predetermined position, to provide said first indication, and for detecting the absence of said magnetic signal when said photosensitive surface is at any position other than said predetermined position to provide said second indication.
16. A copier comprising:
copy producing means including a rotatable photosensitive drum;
cleaning means for preparing said photosensitive drum for image recording use;
a timing wheel coaxially coupled to said drum for rotation therewith, said timing wheel having a plurality of cams thereon, including a large indicating cam and a small synchronizing cam;
a switch mounted adjacent said timing wheel, said switch assuming a first state when engaging either of said cams and assuming a second state when engaging said timing wheel;
first means connected to said copy producing means, said cleaning means, and said switch, responsive to the presence of said second state upon application of power to said copier, for activating said cleaning means and disabling said copy producing means;
second means connected to said switch, responsive to the presence of said first state upon applica-tion of power to said copier, for determining whether said switch is engaged with said synchron-izing cam or with said indicating cam;
third means connected to said second means, said cleaning means and said copy producing means for activating said cleaning means and disabling said copy producing means consequent upon said switch being engaged with said synchronizing cam; and fourth means connected to said second means and said copy producing means for enabling said copy producing means consequent upon said switch being engaged with said indicating cam.
copy producing means including a rotatable photosensitive drum;
cleaning means for preparing said photosensitive drum for image recording use;
a timing wheel coaxially coupled to said drum for rotation therewith, said timing wheel having a plurality of cams thereon, including a large indicating cam and a small synchronizing cam;
a switch mounted adjacent said timing wheel, said switch assuming a first state when engaging either of said cams and assuming a second state when engaging said timing wheel;
first means connected to said copy producing means, said cleaning means, and said switch, responsive to the presence of said second state upon application of power to said copier, for activating said cleaning means and disabling said copy producing means;
second means connected to said switch, responsive to the presence of said first state upon applica-tion of power to said copier, for determining whether said switch is engaged with said synchron-izing cam or with said indicating cam;
third means connected to said second means, said cleaning means and said copy producing means for activating said cleaning means and disabling said copy producing means consequent upon said switch being engaged with said synchronizing cam; and fourth means connected to said second means and said copy producing means for enabling said copy producing means consequent upon said switch being engaged with said indicating cam.
17. The copier of claim 16 wherein said second means comprises means for rotating said photosensitive drum for a predetermined short time interval, wherein said third means is connected to said switch and comprises means for activating said cleaning means and enabling said copy producing means consequent upon said switch being in said second state at the end of said short time interval, and BO980-0??
wherein said fourth means is connected to said switch and comprises means for enabling said copy producing means consequent upon said switch being in said first state at the end of said short time interval.
wherein said fourth means is connected to said switch and comprises means for enabling said copy producing means consequent upon said switch being in said first state at the end of said short time interval.
18. A copier comprising:
copy producing means including a rotatable photosensitive drum;
cleaning means for preparing said photosensitive drum for image recording use;
a timing wheel coaxially coupled to said drum for rotation therewith, said timing wheel having a plurality of cams thereon, including a first number of closely spaced indicating cams at a predetermined-location thereon and a second number of individual synchronizing cams;
means for initiating the rotation of said photosensitive drum upon the application of power to said copier to thereby rotate said timing wheel;
a switch mounted adjacent said timing wheel for engaging said plurality of cams upon rotation of said timing wheel, the output of said switch making a transition when said switch engages one of said plurality of cams and making a trans-ition when said switch disengages from one of said plurality of cams;
first means coupled to the output of said switch and said initiating means for counting the number of transitions at the output of said switch from the time said initiating means rotates said timing wheel;
BO980-0??
second means coupled to the output of said switch, said initiating means and said first means, for detecting the occurrence of twice the first number of transitions within a predetermined short time interval and for disabling said first means upon the occurrence thereof;
third means coupled to said first means and said second means, for providing a first indication if the number of transitions counted by said first means equals twice the sum of said first number and said second number, and for providing a second indication if the number of transitions counted by said first means is not equal to twice the sum of said first means and said second number;
fourth means coupled to said third means and said copy producing means responsive to said first indication, for enabling said copy producing means; and .
fifth means coupled to said third means, said copy producing means and said cleaning means, responsive to said second indication, for activating said cleaning means and disabling said copy producing means.
copy producing means including a rotatable photosensitive drum;
cleaning means for preparing said photosensitive drum for image recording use;
a timing wheel coaxially coupled to said drum for rotation therewith, said timing wheel having a plurality of cams thereon, including a first number of closely spaced indicating cams at a predetermined-location thereon and a second number of individual synchronizing cams;
means for initiating the rotation of said photosensitive drum upon the application of power to said copier to thereby rotate said timing wheel;
a switch mounted adjacent said timing wheel for engaging said plurality of cams upon rotation of said timing wheel, the output of said switch making a transition when said switch engages one of said plurality of cams and making a trans-ition when said switch disengages from one of said plurality of cams;
first means coupled to the output of said switch and said initiating means for counting the number of transitions at the output of said switch from the time said initiating means rotates said timing wheel;
BO980-0??
second means coupled to the output of said switch, said initiating means and said first means, for detecting the occurrence of twice the first number of transitions within a predetermined short time interval and for disabling said first means upon the occurrence thereof;
third means coupled to said first means and said second means, for providing a first indication if the number of transitions counted by said first means equals twice the sum of said first number and said second number, and for providing a second indication if the number of transitions counted by said first means is not equal to twice the sum of said first means and said second number;
fourth means coupled to said third means and said copy producing means responsive to said first indication, for enabling said copy producing means; and .
fifth means coupled to said third means, said copy producing means and said cleaning means, responsive to said second indication, for activating said cleaning means and disabling said copy producing means.
19. The copier of claim 16 or 18 wherein said plurality of cams are on the periphery of said timing wheel.
20. The copier of claim 16 or 18 wherein said plurality of cams are on the side of said timing wheel.
BO980-0??
BO980-0??
21. A copier comprising:
a rotatable photoconductive drum;
a charging station for applying a uniform electrical potential to said photosensitive surface;
an exposure station for forming a latent electro-static image on the periphery of said drum;
a developing station for transforming the latent electrostatic image into a visible image;
a cleaning station for preparing said photosen-sitive surface for image recording use, said exposure station, said developing station, and said cleaning station all being disposed about the periphery of said drum;
a timing wheel coaxially coupled to said drum for rotation therewith, the periphery of said timing wheel including a cam at a predetermined location thereon;
a switch mounted adjacent the periphery of said timing wheel, said switch assuming a first state when engaged by said cam and assuming a second state when not engaged by said cam; and first means connected to said charging station, said exposure station, said developing station, said cleaning station, and said switch, responsive to the application of power to said copier, for sequen-tially activating said charging station, said exposure station, said developing station, and said cleaning station when power is applied to said copier and said switch is in said second BO980-0??
state, and for sequentially activating said cleaning station, said exposure station, said developing station and reactivating said cleaning station when power is applied to said copier and said switch is in said first state.
a rotatable photoconductive drum;
a charging station for applying a uniform electrical potential to said photosensitive surface;
an exposure station for forming a latent electro-static image on the periphery of said drum;
a developing station for transforming the latent electrostatic image into a visible image;
a cleaning station for preparing said photosen-sitive surface for image recording use, said exposure station, said developing station, and said cleaning station all being disposed about the periphery of said drum;
a timing wheel coaxially coupled to said drum for rotation therewith, the periphery of said timing wheel including a cam at a predetermined location thereon;
a switch mounted adjacent the periphery of said timing wheel, said switch assuming a first state when engaged by said cam and assuming a second state when not engaged by said cam; and first means connected to said charging station, said exposure station, said developing station, said cleaning station, and said switch, responsive to the application of power to said copier, for sequen-tially activating said charging station, said exposure station, said developing station, and said cleaning station when power is applied to said copier and said switch is in said second BO980-0??
state, and for sequentially activating said cleaning station, said exposure station, said developing station and reactivating said cleaning station when power is applied to said copier and said switch is in said first state.
22. A copier comprising:
a movable photosensitive surface;
means for measuring the position of said photo-sensitive surface upon application of power to said copier, to thereby infer the status of said copier when power was removed therefrom;
and means for controlling the start-up of copier operations in accordance with the measured position of said photosensitive surface.
a movable photosensitive surface;
means for measuring the position of said photo-sensitive surface upon application of power to said copier, to thereby infer the status of said copier when power was removed therefrom;
and means for controlling the start-up of copier operations in accordance with the measured position of said photosensitive surface.
23. In a copier having a movable photosensitive surface, a method for controlling start-up operation of said copier depending upon the start-up position of said photosensitive surface relative to a predetermined position comprising the steps of:
detecting if said photosensitive surface is at said predetermined position;
activating said copier for producing a copy if said photosensitive surface is at said pre-determined position; and cleaning said photosensitive surface subsequent to producing a copy.
detecting if said photosensitive surface is at said predetermined position;
activating said copier for producing a copy if said photosensitive surface is at said pre-determined position; and cleaning said photosensitive surface subsequent to producing a copy.
24. In a copier having a movable photosensitive surface, a method for controlling start-up ???? ???
operation of said copier depending upon the start-up position or said photosensitive surface relative to a predetermined position comprising the steps of:
detecting if said photosensitive surface is at any position other than said predetermined position;
cleaning said photosensitive surface if said photosensitive surface is at any position other than said predetermined position; and activating said copier for producing a copy on the cleaned photosensitive surface.
operation of said copier depending upon the start-up position or said photosensitive surface relative to a predetermined position comprising the steps of:
detecting if said photosensitive surface is at any position other than said predetermined position;
cleaning said photosensitive surface if said photosensitive surface is at any position other than said predetermined position; and activating said copier for producing a copy on the cleaned photosensitive surface.
25. In a two cycle copier having a first cycle for copying an image via a movable photosensitive surface and a second cycle for cleaning said photosensitive surface for image recording use, the method of controlling the operation of said copier upon application of power thereto com-prising the steps of:
detecting if said photosensitive surface is at a predetermined position;
activating said first cycle if said photosen-sitive surface is at said predetermined position;
and activating said second cycle at the conclusion of said first cycle.
detecting if said photosensitive surface is at a predetermined position;
activating said first cycle if said photosen-sitive surface is at said predetermined position;
and activating said second cycle at the conclusion of said first cycle.
26. In a two cycle copier having a first cycle for copying an image via a movable photosensitive surface and a second cycle for cleaning said photosensitive surface for image recording use, the method of controlling the operation of said copier upon application of power thereto com-prising the steps of:
detecting if said photosensitive surface is in any position other than a predetermined position;
activating said second cycle if said photosen-sitive surface is in any position other than the aforesaid predetermined position;
activating said first cycle at the conclusion of said second cycle; and re-activating said second cycle at the conclusion of said first cycle.
detecting if said photosensitive surface is in any position other than a predetermined position;
activating said second cycle if said photosen-sitive surface is in any position other than the aforesaid predetermined position;
activating said first cycle at the conclusion of said second cycle; and re-activating said second cycle at the conclusion of said first cycle.
27. The two cycle copier of claims 25 or 26 wherein said predetermined position is the position of said photosensitive surface at the conclusion of said second cycle.
28. In a copier having copy producing means including a rotatable photosensitive drum, cleaning means for preparing said photosensitive drum for image recording use, a timing wheel coaxially coupled to said drum for rotation therewith, said timing wheel having a plurality of cams thereon including a large indicating cam and a small synchronizing cam, and a switch mounted adjacent said timing wheel, said switch assuming a first state when engaging either of said cams and assuming a second state when engaing said timing wheel, the method of controlling the start-up of copier operations upon application of power to said copier comprising the steps of:
determining the state of said switch;
activating said cleaning means and disabling said copy producing means if said switch is in said second state;
ascertaining whether said switch is engaged with said indicating cam or said synchronization cam if said switch is in said first state;
activating said cleaning means and disabling said copy producing means if said switch is engaged with said synchronization cam, and enabling said copy producing means if said switch is engaged with said indicating cam.
determining the state of said switch;
activating said cleaning means and disabling said copy producing means if said switch is in said second state;
ascertaining whether said switch is engaged with said indicating cam or said synchronization cam if said switch is in said first state;
activating said cleaning means and disabling said copy producing means if said switch is engaged with said synchronization cam, and enabling said copy producing means if said switch is engaged with said indicating cam.
29. The method of claim 28 wherein said ascertaining step comprises the steps of:
rotating said photosensitive drum for a predeter-mined short time interval; and determining the state of said switch at the end of said predetermined short time interval.
rotating said photosensitive drum for a predeter-mined short time interval; and determining the state of said switch at the end of said predetermined short time interval.
30. In a copier having copy producing means including a rotatable photosensitive drum, cleaning means for preparing said photosensitive drum for image recording use, a timing wheel coaxially coupled to said drum for rotation therewith, said timing wheel having a plurality of cams thereon including a first number of closely spaced indicating cams and a second number of individual synchronizing cams, and a switch mounted adjacent said timing wheel for engaging said plurality of cams the output of said switch making a transition when said switch engages one of said plurality of cams and making a transition when said switch disengages from one of said plurality of cams, the method of controlling start-up copier operations upon the application of power to said copier comprising the steps of:
rotating said photosensitive drum to thereby rotate said timing wheel, counting the number of transitions at the output of said switch upon rotation of said drum;
detecting the occurence of twice said first number of transitions within a predetermined short time interval;
stopping the counting of said transitions upon detecting the occurence of twice said first number of transitions within said predetermined short time interval;
comparing the number of transitions counted from the time rotation of said drum began until counting was stopped with twice the sum of said first number and said second number;
enabling said copy producing means if the number of transitions counted is equal to twice the sum of said first number and said second number; and activating said cleaning means if the number of transitions counted is not equal to twice the sume of said first number and said second number.
rotating said photosensitive drum to thereby rotate said timing wheel, counting the number of transitions at the output of said switch upon rotation of said drum;
detecting the occurence of twice said first number of transitions within a predetermined short time interval;
stopping the counting of said transitions upon detecting the occurence of twice said first number of transitions within said predetermined short time interval;
comparing the number of transitions counted from the time rotation of said drum began until counting was stopped with twice the sum of said first number and said second number;
enabling said copy producing means if the number of transitions counted is equal to twice the sum of said first number and said second number; and activating said cleaning means if the number of transitions counted is not equal to twice the sume of said first number and said second number.
31. The method of claim 30 wherein said first rotating step is preceded by the step of disabling said copy producing means.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US18215480A | 1980-08-28 | 1980-08-28 | |
| US182,154 | 1980-08-28 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1173890A true CA1173890A (en) | 1984-09-04 |
Family
ID=22667277
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000380146A Expired CA1173890A (en) | 1980-08-28 | 1981-06-18 | Control of copier start-up operations |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0046852B1 (en) |
| JP (1) | JPS5754971A (en) |
| CA (1) | CA1173890A (en) |
| DE (1) | DE3162795D1 (en) |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE792640A (en) * | 1971-12-17 | 1973-03-30 | Ibm | ELECTROSTATIC TRANSFER REPRODUCTION APPARATUS |
| JPS5830585B2 (en) * | 1973-04-30 | 1983-06-30 | 株式会社リコー | Cleaning information |
| US3834807A (en) * | 1974-02-14 | 1974-09-10 | Ibm | Copier with leading edge image control |
| US3982830A (en) * | 1974-12-06 | 1976-09-28 | International Business Machines Corporation | Magnetic bead carryout reduction by altering the developer's bias voltage |
| JPS5931067B2 (en) * | 1974-12-13 | 1984-07-31 | キヤノン株式会社 | copying device |
| US4185910A (en) * | 1976-06-30 | 1980-01-29 | Tokyo Shibaura Electric Co., Ltd. | Photoconductive member cleaning device using a magnetic brush for electrostatic copying machines |
-
1981
- 1981-06-18 CA CA000380146A patent/CA1173890A/en not_active Expired
- 1981-07-06 DE DE8181105224T patent/DE3162795D1/en not_active Expired
- 1981-07-06 EP EP19810105224 patent/EP0046852B1/en not_active Expired
- 1981-07-10 JP JP56107155A patent/JPS5754971A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| EP0046852A1 (en) | 1982-03-10 |
| EP0046852B1 (en) | 1984-03-21 |
| JPS5754971A (en) | 1982-04-01 |
| DE3162795D1 (en) | 1984-04-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |