Title:
System for printing on a moving web
United States Patent 3908542
Abstract:
A system is disclosed for generating an actuation signal for actuating a hammer in a machine for printing predetermined indicia at preselected locations on a moving web. The system includes three photocells and logic circuitry including a clock, an up-down counter, flip-flops and several gates.
Application Number:
05/536457
Publication Date:
09/30/1975
Assignee:
Roberts Numbering Company (Brooklyn, NY)
Other Classes:
118/669, 118/697, 400/154.5, 400/583.3
International Classes:
B41J7/36; B41J9/44; G06K15/06; B41J7/00; B41J9/00; G06K15/02; (IPC1-7): B41J9/26
Field of Search:
197/48-55 101
Primary Examiner:
Shapiro, Paul E.
Attorney, Agent or Firm:
Lerner, David, Littenberg & Samuel
Claims:
What is claimed is
1. A system for generating an actuation signal for activating a hammer in a machine for printing predetermined indicia at preselected locations on a moving web; said system including:
2. The system for generating said actuation signal as defined in claim 1 also including:
3. The system is for generating said actuation signal as defined in claim 2 in which said sixth means inhibits said up-down counter from providing said actuation signal until after the next occurrence of said first position signal.
4. The system as defined in claim 1 in which said first and second means are photo-sensitive devices mounted at fixed positions in said machine.
5. The system for generating said actuation signal as defined in claim 4 also including:
6. The system is for generating said actuation signal as defined in claim 5 in which said sixth means inhibits said up-down counter from providing said actuation signal until after the next occurrence of said first position signal.
7. The system as defined in claim 6 in which said fifth means is a photo-sensitive device mounted at a fixed position in said machine.
Description:
FIELD OF THE INVENTION
This invention relates to numbering on a moving web and particularly to numbering on a moving web without stopping the movement of the web.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 3,734,010 which issued to Richard L. Le Gault and me on May 22, 1973, and is entitled HIGH SPEED NUMBER PRINTER, discloses a numbering station for a high speed printing machine in which a web moving therethrough is printed upon at other stations in the printing machine. At the numbering station, a plurality of parallel numbering wheels mounted on a common axis are each individually positioned by a separate stepping motor in response to electric signals applied thereto. A ribbon passed between the numbering wheels and the moving web transfers ink to the web when a platen or hammer mounted in back of the web is periodically actuated.
When the web is moving at a constant speed, the hammer can be actuated a fixed time before the printing is to occur so that the printing occurs at the appropriate position on the web. The reason the hammer is actuated before actual printing is desired, is that a predetermined time interval elapses between the actuation of the hammer and actual striking of the hammer onto the web. When the web is moving at a constant speed, the position to be marked is sensed a predetermined distance before the web is in position for printing. Since it is moving at a constant speed, it takes a predetermined time to move from the sensed position to the hammer position.
It has been found that the web does not move at an exactly constant speed and that the equipment to control the web to move at an exactly constant speed, would be prohibitively expensive. Still in numbering upon a moving web it is necessary that accurate placement of the numbers be achieved.
The problem of web speed variation is not found in the other printing stations since there is no striking hammer with its accompanying time delay to cause location variations.
BRIEF DESCRIPTION OF THE INVENTION
To overcome the problems set forth above, a system has been developed for generating an actuation signal for actuating the hammer in the machine at the numbering station which prints predetermined indicia at preselected locations on the moving web. The system includes a first device for sensing when the preselected locations are at a first position with respect to the numbering station to provide a first position signal and a second device for sensing when the preselected locations are at the second position with respect to the numbering station to provide a second position signal. A clock signal drives an updown counter which is controlled by the first and second position signals for counting the clock signal in a first direction in response to the first position signal and in a second direction in response to the second position signal. The system also includes circuitry responsive to the updown counter reaching a predetermined count for providing the actuation signal.
In the preferred embodiment of this invention a third device is provided for sensing when the pre-selected locations are at a third position with respect to said numbering station for providing a third position signal and circuitry is also provided which is responsive to the third position signal for generating the actuation signal if the actuation signal has not already been provided since the last occurrence of the third position signal.
DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the invention reference should be made to the following detailed description and drawings in which:
FIG. 1 is a schematic showing of the relationship of the system of this invention to the machine disclosed in U.S. Pat. No. 3,734,010 which is incorporated herein by reference; and
FIG. 2 is a block diagram showing a system embodying the principle of this invention.
DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, we see a block diagram showing the interrelationship with the system of this invention and the numbering station disclosed in U.S. Pat. No. 3,734,010. In FIG. 1 the numbering wheel 19 corresponds to the numbering wheel 19 in the above referred-to patent while the hammer assembly 11 and hammer 46 correspond to the same elements in the prior patent. In like fashion the web of paper 12 is shown as running between the hammer 49 and the wheel 19.
The photocell 48 likewise corresponds to the photocell 48 in the prior patent. In addition, in this embodiment, two additional photocells 51 and 52 are mounted along the path of the web 12. The photocell 51 is mounted midway between the photocell 48 and the hammer 46. The photocell 52 is mounted opposite the web 12 at the same level as the hammer 46. It should be clear that the photocell 52 is positioned so that light from the web 12 is not blocked by the wheels 19 so that markings on the web 12 can be sensed thereby. The web 12 has a position mark thereon as the web 12 in the prior patent does. In accordance with the teachings of this invention the position mark on the web 12 sequentially actuates the photocells 48, 51 and 52 to provide first, second and third position signals on lead 53, 54 and 56, respectively. These leads are fed to a logic circuit 57 which generates an actuation signal on a lead 58.
Referring now to FIG. 2, we see the details of the logic circuit 57 and its connection to the photocell 48, 51 and 52 as well as the lead 58 which applies the actuation signal to the hammer assembly 11.
In order to actuate the hammer assembly 11, when the proper portion of the web 12 is adjacent thereto, the photocell 48 applies a signal via lead 53 to an updown counter 59 when the position marking on the web 12 passes therebeneath. The signal from the photocell 48 enables the up-down counter 59 to count clock pulses from its initial count. The signal from the photocell 48 is also applied to a flip-flop 62 by lead 63, thereby setting the flip-flop 62 to inhibit an AND gate 64 from passing any pulses.
When the position mark on the web 12 passes beneath the photocell 51, the photocell 51 applies a signal to the up-down counter 59 to reverse the direction of its count so that the up-down counter 59 now starts counting the clock pulses from the clock 61 in the opposite direction. The signal from the photocell 51 also resets the flip-flop 62 to enable the AND gate 64 to pass pulses from the up-down counter 59. It should be noted that the number in the up-down counter 59 at the time of the reversal caused by the pulse from the photo detector 51 is a measure of the time it took for the position marker on the web 12 to travel from the photo-responsive device 48 to the photo-responsive device 51. This is a measure of the average speed that the web was traveling at during that short time interval that the position mark was traveling from photocell 48 to 51. For all intents and purposes this can be considered the average speed of the web 12 as it travels from the photocell 51 to the hammer 46.
When the up-down counter 59 reaches a predetermined count, a decoder 66 applies a pulse to the AND gate 64. The AND gate 64 now enabled by flip-flop 62, passes the pulse via lead 68 and OR gate 69 to the lead 58 to actuate the hammer. The pulse or lead 58 is applied by lead 71 to reset the up-down count 59 to its initial count.
It should be noted that the predetermined number which the decoder 66 provides the pulse at is determined in accordance with the distance between the photo-responsive device 51 and the hammer 46. Since the delay time of the hammer 46 is known, and the distance from the photocell 51 to the hammer 46 is known, the count in the up-down counter 59 which is related to the distance between the photo-responsive devices 48 and 51, is employed to provide the actuation signal a fixed number of counts (and therefore a fixed time) before the proper portion of the web 12 is adjacent to the hammer 46. In this way the actuation pulse is provided so that the hammer 46 will in fact strike the web 12 when the proper portion is adjacent thereto.
Another way of looking at the system of this invention is that the number in the up-down counter 59 at the time of the pulse provided by photo-responsive device 51, is a number related to the distance between the photo-responsive devices 48 and 51 and the speed of the web 12. Since each number in the up-down counter 59 represents a time interval determined by the clock 61 and the distance between the photo-responsive devices 51 and 52 are known, the counting down until a certain number of counts are left until the hammer 46 should be reached, insures that a fixed time will elapse between that time and the time the proper portion of the web 12 is reaching the hammer 46. This time is the number of counts left times the interpulse period of the clock 61.
It should be noted that the distance between the various photo-responsive devices 48 and 51 and the hammer 46 need not be of any particular relationship but must merely be known in order to pick the predetermined count for providing the actuation signal.
If, for some reason, the decoder 66 does not detect the predetermined count before the predetermined position on the web 12 reaches the hammer 46, the photocell 52 provides a third position signal via lead 56, AND gate 72, lead 73 and OR gate 61 to the lead 58 as an actuation signal. To prevent the photocell 52 from providing an actuation pulse when not needed a monostable flip-flop 67 inhibits the signal on the lead 56 from passing through the AND gate 72 if an actuation signal is provided on the lead 68 within a predetermined time prior to the signal appearing on the lead 56. The conditions under which the pulse is needed from the photocell 52 is when the web is going very slowly and the predetermined number is not reached or a system error of some sort occurred. If the web is going very slowly the system will still function properly since the hammer delay time will not affect the position of the printing very greatly when the web 12 is moving slowly. It is, of course, possible to add additional circuitry which would disable the updown counter 59 if the count became very high and allowed the photocell 52 to actuate the hammer 46.
While this invention has been described with respect to a particular embodiment thereof, numerous others will become obvious to those of ordinary skill in the art in light thereof.