JPH07285698A - Conveying device - Google Patents

Abstract

PURPOSE: To accurately position a support by forming a constant crossed electrode pattern on a belt of a flexible loop shape, and attracting the support by applying a strong electrostatic field between electrodes. CONSTITUTION: A belt loop 10 is formed of flexible reinforced rubber, and an electrostatic hold-down grid (an electrostatic installation lattice) 32 is incorporated. The electrostatic installation lattice 32 forms a series of separated and crossed finger-like electrodes 34 extending by crossing the belt loop 10. When applying a voltage on the electrodes 34, a strong electrostatic field is generated between the electrodes 34, so that electrostatic attractive force is generated in the belt direction to a support S placed on the belt loop 10 to thereby reliably fix the support S on the belt loop 10 to accurately position the support by preventing a slide.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carrier device, and more particularly to a carrier device capable of holding an electrostatic support for a printing press and other devices requiring precise alignment.

[0002]

BACKGROUND OF THE INVENTION In the field of mechanical equipment, there are various transport devices for transporting a support or article from one station to another for performing successive operations on the support or article. For example, in color printing, one sheet of paper support is moved from one printing station to the next and the color is deposited continuously on top of it, but at each successive printing station an image is constructed. Accurate registration of the color dots to be performed. Accuracy in registration is required because the differently colored inks on top of each act as a multiplex filter that, when superposed, can produce a wide range of tones. Typically, it is desirable to maintain registration to an accuracy of about ± 5 micrometers (μm) per 50 square micrometers (μm ² ) printed dots.

It is not just printing that is concerned with accurately transporting articles across successive workstations. For example, in the manufacturing process of integrated circuits, semiconductor wafers are accurately transported to successive exposure, masking, etching and leadframe mounting stations to manufacture the final product. If the wafer is mispositioned, the product will be wasted and the manufacturer will be at a significant cost. Sorting mail is another area of interest.

[0004]

The carrier of the support is a belt or a cylinder, depending on the specific application such as printing, sorting of mail, and the like. The carrier of the support can even be a so-called moving bed type conveyor, in which one carrier part reciprocates with respect to the fixed part and the moving part moves back and forth. The fixed part prevents the article from slipping back.

Conventionally, supports such as mechanical grippers or vacuum holders have been used, usually using expensive and cumbersome precision mechanisms to securely hold the support or other article on the carrier. Accurate transport of other articles has been made. Paper cylinders and other transport devices used in the printing industry are not only complicated and costly due to their sophisticated internal gripping mechanisms, but mechanical grippers with actuators and cams significantly limit cycle times. Therefore, the device speed itself is limited. A further disadvantage of these conventional devices is that they tend to damage the support or other article that they grip or clamp. Furthermore, both the mechanically actuated holding mechanism and the vacuum actuated suction device are quite noisy and thus interfere with personnel working in the vicinity of the machines.

[0006] Therefore, various supports such as paper, plastic sheets, thin foils and other normally flat media, with minimal power, are safe and reliable at operating speeds substantially higher than those currently achievable. Needs to be transported in degrees.

[0007] Further, since belt-type conveyance is required for highly accurate registration in color printing applications,
Because of the lateral wandering of the belt, it is typically not used to advance paper or other print support from one printing station to the next. It would be desirable to provide a belt-type conveyor that is capable of achieving good registration accuracy in printing or other workstations where belt-type conveyors are available.

Accordingly, it is an object of the present invention to provide an improved apparatus for transporting supports or other flat articles which achieves accurate alignment.

Another object of the invention is to provide a carrier device of the above type which does not use mechanical means to hold the support to the carrier carrying it.

Yet another object of the present invention is to provide a carrier device that can safely and reliably carry a variety of different articles including thin and brittle supports.

Another object of the present invention is to provide a transport device particularly suitable for color printing applications.

Another object of the invention is to provide a carrier device which is quiet and efficient in that it requires a minimum of power.

Yet another object of the present invention is to use a drive belt carrier, but with which articles can be conveyed over a continuous workstation and at which precise alignment can be achieved. A transport device is provided.

Other objects of the present invention will become apparent in the following, and some will be actually described.

[0015]

The present invention is characterized by a structure, a combination of constituent elements and an arrangement of parts, which are exemplified in the following detailed description, and the scope of the present invention is defined by the scope of claims. As described in.

Broadly speaking, the transport apparatus of the present invention transports the support over successive workstations,
It comprises a moveable carrier which makes it possible to carry out various operations at selected positions of the support. In the following, a transport device incorporated in a printing machine for performing color printing on a printing support such as paper transported through the printing machine will be particularly described. However, it should be appreciated that various aspects of the carrier may be utilized for other applications that require precise positioning of a support or other flat article. Further, in this document, the explanation will be given mainly on the conveying device incorporating the belt type conveying body. However, it is also possible to apply the various features of the present invention to transport using a drum type transporter or a reciprocating (moving bed) transporter.

A belt-type carrier in the form of a flexible belt loop is spanned by a pair of rollers, at least one of which is rotated by a suitable motor drive. Upper stretch of belt loop (str
The (etch) part penetrates a plurality of workstations. In the case of a printing press, the workstation comprises a series of printing stations arranged to produce different color prints on a support carried by a carrier.

An electrostatic hold down grid is incorporated into the belt loop to maintain the position of the support relative to the carrier. This is provided by a pattern of interlaced electrodes embedded in the belt. A constant potential is applied to the electrodes adjacent to these electrodes, which creates a strong electrostatic field between the electrodes. The electrostatic field lines extend above the surface of the belt to induce a certain amount of capacitive charge in the support to interact with the support, and a strong electrostatic attractive force to the belt is generated on the support.

As will be described in more detail below, provision is made to deactivate the electrodes at selected locations along the belt loop path so that the support is no longer drawn to the belt. For example, when the electrode approaches the exit end of the belt loop, the electrode is deactivated,
The support can be moved away from the carrier or transferred to another carrier without being transported to the underside of the belt loop.

As stated above, in printing operations, it is very important to overlay the color dots in precise registration with one another at various printing stations.
For this reason, belt type carriers are generally not used for the purpose of transporting print supports through the printing press, as the belt may wander in the transverse direction or the speed of the belt may fluctuate for some reason. However, although the conveyor of the present invention uses a belt type carrier, it preferably has a group of thin longitudinal parallel lines extending across the entire belt loop near one edge of the belt loop. Forming it in the belt with the electrodes eliminates the above problems. These lines are engraved with a line pattern on its working surface which forms an interference filter with the lines on the belt which detects slight transverse movements of the belt and which produces a signal indicating transverse displacement of the belt. Is detected by the optical sensor. Also embedded in the belt is a series of longitudinal timing marks that form an optical clock track that extends throughout the belt loop. These marks are detected by a second optical sensor which produces an output signal indicating the speed of the belt. This feature allows the longitudinal position of the belt to be accurately determined at any time, even when the transport speed fluctuates, thus initiating any movement required at a certain position of the belt. It becomes possible to do.

When the above two signals are input to the controller, the controller 1) adjusts the position of the belt to a certain extent by a unique variable geometry roller, which will be described later, and 2) at various work stations, to adjust the position of the work member. Fine adjustment of the transverse and longitudinal positions allows any of the workpiece members to operate in exactly the correct position on the support being carried by the belt.

That is, the apparatus of the present invention ensures that the support is held electrostatically in place on a belt or other carrier and then when the support arrives at successive workstations, the support is accurately positioned. Maintain proper alignment. To this end, such devices track the movement of a belt or other carrier and apply a signal to various workstations to move the work members of the workstations as the support arrives at each workstation. Be sure to place it in the correct and correct position with respect to the support. The present apparatus can thus perform the “expected positioning” and can accurately link the support member position and the work member position with an accuracy of less than ± 5 μm.

When incorporated into a color printing machine, the belt type transport of the present invention incorporates the belt as it wanders transversely due to the inherent periodicity of the control mechanism which continuously adjusts the belt as it moves. Deviation is predicted. Therefore, at each printing station the position of the writing head of the printing station cooperating with the printing cylinder is continuously adjusted in anticipation of the arrival of color dots from the preceding station, so that the next dot is always exactly the previous one. Superimposed on top. That is, the printheads of the various printing stations of the printing press are subject to the calculation according to the calculation made by the machine controller, which integrates knowledge of the movement of the belt and its adjusting periodicity with knowledge of the required timing and position of successive printheads. , There is continuous microscopic movement and transverse movement as the image is written on each print cylinder at that station. This predictive registration control method prints with a color overlay accuracy that could not be achieved using conventional printing methods, which typically achieve achievable registration accuracy of ± 100 micrometers or less. It becomes possible.

For a fuller understanding of the nature and purpose of the present invention, reference should be made to the following detailed description in conjunction with the accompanying drawings.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Reference is made to FIG. 1 showing a transport apparatus of the present invention incorporated into a three color printing press. However, the transport apparatus of the present invention is essentially a four-color or false five-color printing machine, or
It should be understood that the flat support can be moved towards a continuous workstation to serve a variety of other position sensitive operations on the support. is there.

The transport system includes a flexible belt loop 10 of a suitable strong, resilient and tear resistant material such as reinforced rubber or plastic material. Belt 10 is spanned between a pair of rollers 12 and 13, one of which, roller 13, is a suitable motor 14 controlled by system controller 15.
Can be driven by. And the belt loop of the upper extending portion 10a on a supported substrate S different colors of three colors on printable similarity of printing stations 16 along the belt loop 10 a, 16 b and 16 c are spaced There is. For example, the printing stations 16 a to 16 c are cyan, magenta and yellow primary colors can be printed, respectively.

When the printing press operates, the arrow A in FIG.
The belt loop 10 is rotated in the clockwise direction indicated by. A support S, i.e. a sheet of paper, is continuously placed by means of a suitable feeder (not shown) on the upper extension 10a of the belt loop. When each support S is conveyed through successive printing stations 16 a to 16 c,
Images of different colors are printed on the support. As noted above, in the exemplary device, these colors are cyan, magenta and yellow. In fact, these three printed images represent the three color components or color separations of the original color printed document or image, requiring that the image be printed on the support S in precise registration. . The apparatus of the present invention, first of all, printing stations 16 a to 16 c to the supports, which are placed on the belt loop 10 is continuously
Each of the supports as they are conveyed through the belt loop 1
Hold it firmly on the 0, second, the belt loop 10
The printing performed at each printing station is adjusted to account for wobbling or speed variations to ensure that the above is achieved.

In order to achieve the first object, the belt loop 10 holds each support S when it is placed on the left end of the belt loop and when the support is conveyed through the printing machine. Holding the support flat against the belt,
And an electrostatic hold down grid (er) indicated generally at 32 which releases the support when it reaches the exit or right end of the belt loop.
electrostatic hold-down gri
d) is incorporated.

As best seen in FIGS. 1 and 2, an electrostatic holddown grid (hereinafter referred to as an electrostatic mounting grid) 32 is a series of spaced, interlaced, extending across the belt loop 10. Finger-shaped electrodes 34 and 36 that are connected to each other, and the connection of the electrodes is provided so as to go around the entire belt loop. The corresponding ends of the electrodes 34 are connected to a common electrode or bus 34a that extends around the entire belt loop near the left edge of the belt loop. Electrode 36 on the right side near the edge of the same common electrode or bus 36 a belt loop
Connected to.

The electrodes are preferably placed underneath a high coefficient of friction film 38, such as neoprene or silicone rubber, deposited on at least the entire outer surface of the belt loop. This film 38 not only enhances the retention of the belt loop 10 on the support S, but also protects the electrodes from the effects of chemical corrosion or condensation that may occur under certain operating conditions. The film 38 also insulates the electrodes and prevents the hands from directly contacting such electrodes.

During operation of the device, the power source 42 supplies the bus 34.
potential difference of approximately 1000 volts is brought to a and 36 a. Power may be connected to the electrode by the bus 44 a and 44 b or suitable rolling contact as shown in FIG. 1.
These connections are also referred to as "capacitive coupling".
ve coupling), whereby the belt loop is placed in close proximity to the mounting grid at some convenient location, such as the end of the belt loop rotating around the rollers 12 or 13. A capacitor plate (not shown) is used to displace the electrons and holes to induce charge in the mounting grid.

When the electrodes 34 and 36 are energized, they create a strong electrostatic field between the electrodes along their length. The lines of electrostatic force E reach above the surface of the film 38 and interact with the support S placed on the belt loop 10 to induce capacitive charge in the support. This in turn causes an electrostatic attraction force on the support towards the belt. However, this attractive force is effective only at a short distance of about the thickness of the support, and only when the support is in intimate planar contact with the belt. This property prevents two documents from being fed together and is therefore used when transporting, for example, for sending items such as mail, signatures in a bookbinding office, or for sorting. Be beneficial to.

Accordingly, the electrostatic mounting grid 32 cooperates with the high friction film 38 to secure the position of the support S mounted on the belt loop 10. In addition, the features of electrostatic mounting are effective over the entire area of the support, and in fact
It is proportional to the area of the support. The force F that resists the sliding of the support on the belt loop 10 is represented by the following equation: F = Aeμ ₀ , where A is the area of the support S and e is the unit area per unit area. It is an attractive force, and μ ₀ is an electrostatic friction coefficient.

On the other hand, the peeling resistance is effective only in the line region smaller than e because the width of the line is smaller than the unit area, so that the support can be easily peeled off from the belt 10. From this it becomes clear that the support S can easily be disengaged at the end of the belt loop 10 into a starting path which is usually tangential to the roller 14.
Therefore, in most cases, the support S should be provided with the rigidity of ordinary paper that is discharged from the outlet of the belt loop 10 shown in FIG.

In accordance with the present invention, for example, to facilitate handling of a very thin and fragile support, or the support may be lifted at the opposite end of the belt loop 10 and ejected from the carrier. Electrostatic mounting grid 3 at any zone or position in the belt path to ensure
It is possible to be prepared to suspend activity 2 above.
That is, the fragile support does not have inherent rigidity. Therefore, it may be entrained in the roller 14 along with the belt and travel to the underside of the belt loop, possibly to an undesirable position. Therefore, in order to help the support S separate from the belt loop, a suitable electrode 34 and / or
Alternatively, 36 may be de-energized to deactivate the electrostatic mounting grid 32. In the illustrated apparatus, this is achieved by the respective electrodes 36 through a small photoelectric resistor 46 connected to the respective buses 36 a. The resistance of the resistor is inversely proportional to the intensity of light incident on itself. Thus, each counter 46 is essentially being adapted when not illuminated by light sever the connection between the electrode 36 associated with itself and its bus 36 a.

The exemplary electrostatic mounting grid 32 is disabled at selected locations or zones of the belt path by shielding the photoresistor 46 from light at those locations. For example, to disable the grid below the upper extending portion 10 a of the belt, as shown in FIGS. 1 and 3, by arranging the light shield 48 below the end and around the belt path, the belt loop 10 Allows the support S to be lifted and released.

The device of the present invention tightly adjusts the transverse position of the belt and the printing of the image on the support when the position of the support S is securely fixed on the belt loop 10.
To compensate for the remaining operation of the belt loop 10 by the printing stations 16 a to 16 c that could prevent proper registration of the image that is being printed onto the support. For this, the timing track 5 preferably consisting of a series of opaque timing or clock marks 52 a spaced along the said belt loops on one edge of the belt loop
2 is incorporated in the belt loop 10. The truck 52 may be installed at the same time as the grid 32 is installed. These timing lines are detected by an optical detector 54 which produces an output signal corresponding to the controller 15. Therefore, the timing track 52 and the detector 54 together constitute the master clock of the device.

Further, a belt position track, generally indicated at 56 in FIG. 2, is incorporated into the belt loop 10 along track 52, preferably near one edge of belt loop 10. The track 56 is a group of narrow extending across the belt loop 10 consists of spaced parallel opaque lines 56 a. In the illustrated apparatus, track 56 is provided with five such lines. These lines are sensed by a measurement detector 58 mounted on the machine frame, immediately beyond the roller 12. The detector 5
8 is a grating type detector similar to that described in US Pat. No. 3,584,015, the contents of which are incorporated herein by reference, the detector corresponding to a track 56 pattern image. , And thus also has the structure of a grid. With suitable pick-up elements, the grid-shaped image position of the track relative to the grid-shaped detector 58 produces a signal from the detector which indicates the transverse position of the belt relative to a reference position, such as the machine centerline. The detector output is accurate to less than 1 micrometer. Signal from the detector 58 is sent to the controller 15, not only to minimize the wandering of the transverse direction of the belt, as will be described later, the printing stations 16 a to 16
Adjust the printing on the support S by c, the upper extending portion 10 a of the belt loop as the printing station has the
It is also used to allow printing in precise registration on a support S fixed on it.

To maintain the transverse position of the belt,
The device of the present invention incorporates a unique roller 12 that moves laterally across the belt 10 either at one end of the belt and then at the other end of the taper, or vice versa. In this apparatus, the roller 12 is slightly deformed into a conical shape so that the movement of the belt 10 in the transverse direction can be immediately guided while the belt 10 makes a half turn around the roller 12. The transverse displacement of the belt is continuously monitored and a servo system adjusts the conicity of the rollers 12 to maintain the belt at a desired position, such as the machine centerline.

Reference is made to FIGS. 3 and 4 which show the roller 12 in more detail. Although only the left end portion of the roller is shown in FIG. 3, its right end portion is omitted because it is a mirror image of the left end portion. The roller 12 includes a cylindrical central body 62, and the central body has a plurality of shafts 64 projecting in the axial direction from both ends thereof. Reduced diameter end 64 a of each shaft 64
Is journaled to the machine frame 65. Also, it is threaded on the shaft portion 64 b of the immediately inside the machine frame. An annular roller end member 66 is slidably supported on each shaft 64. Each member 66 is slidably housed on a corresponding shaft 64 and abuts against an adjacent end of the central body 62.
6 a . From the base 66 a to the base 66 a
Annular cylindrical portion 66 b having a portion 66 c constricted in the vicinity is extended in the axial direction. As best seen in FIG. 4, the portion 66 b is slit longitudinally,
Forms a plurality of fingers 68, each finger part 66 c
At, it can be freely bent in the radial direction around the axis. The outer diameter of each end member 66 is the same as the outer diameter of the roller body 62 and thus forms a variable diameter extension thereof. The roller body 62 and the end member 66 are covered with a sleeve 70 made of an elastic material such as rubber.

As shown in FIG. 3, portions 66 of the end member b
The inner wall 72 is tapered to form a conical surface, the radius of which decreases with distance from the end of the roller 12. On each shaft 64 is in engagement with the internal surface 72 annular wedge 74 is disposed slidably with conical outer surface 74 a of the cone angle corresponds to the cone angle of the inner wall surface 72 There is. In addition, the spur gear 76 with the threaded axial opening 78 is wedge 74
It is screwed to the shaft portion 62 b between the machine frame 65 and. Therefore, when the spur gear 76 rotates in one direction,
The corresponding wedge 74 will be pushed further into the adjacent end of the roller 12. This action associated end member 56 b is extended in the radial direction, the diameter of the roller is increased in the corresponding end of the roller 12. On the other hand, the spur gear 76 is rotated in the opposite direction, because the can not make any forces wedge 74, between the wedge is between the wedge 74 and the roller end member portions 66 a which the relevant set pressure The coiled spring 82 is pushed outwardly toward the corresponding end of the roller. As a result, the diameter of the end of the roller 12 is reduced.

Each spur gear 76 can be bidirectionally rotated on its shaft 64 by a meshing gear 86 which rotates together with a shaft 88a of a synchronous pulse reversible servomotor 88 mounted on the machine frame 65. Each motor 88 is capable of rotating its associated spur gear 76 faster or slower than the roller 12, which adjusts the conicity of the corresponding end of the roller 12 by moving the corresponding wedge 74 in and out.

[0043] The position of the end member 66 b of the shape and the base 66 on a, by reducing the resilient roller sleeve 70 when the wedge 74 which relationship is pulled out to the outside, roller 1
It has to be understood that it is possible to determine that the diameter of the two corresponding edges is smaller than the diameter of the central part of the roller. Therefore, by properly positioning the wedge 74 on the shaft 64, the opposite end portions of the rollers can be adjusted to make their diameters smaller, equal, or larger than the diameter of the central portion of the rollers. It will be possible. That is, by properly positioning the wedges 74 at both ends of the roller, it becomes possible to vary the conicity of the roller as a whole in both axial directions.

[0044] In the illustrated apparatus, the controller 15 in accordance with the output signal from the detector 58 to the motor 88 for adjusting the conicity of the roller 12 to monitor the deviation of the transverse direction of the upper extending portion 10 a of the belt (Fig. 1) of the It is controlled by a standard servo circuit. The servo tends to maintain the belt within a very close tolerance at a selected position in the transverse direction, for example the machine centerline. As soon as the transverse movement of the belt is detected by the detector 58, a signal is sent to the controller 15, which controls one or both motors 88 to send in or out wedges. Adjust the conicity of the roller 12 by the amount required to return the belt to the center position.

As mentioned above, while the movement of the belt 10 is precisely adjusted to minimize its transverse movement,
In addition, provision is made in the apparatus to compensate for residual motion of the belt that may be caused by belt irregularities or slight delays or perturbations in the belt position servo circuit.

[0046] As described above, the printing stations 16 a to 16 c are different color inks, respectively, for example, those identical all in addition be printed with a cyan, magenta and yellow in subtractive color inks . Each printing station includes a belt upper extending portion 10 a printing cylinder 92 and the belt upper extending portion 10 a anvil cylinder 94 disposed downward is arranged above. All cylinders 92, 94 is supported by a rotatable machine frame so as to be parallel to the belt rollers 12 and 14 so that the top extending portion 10 a of the belt loop 10 is in rolling contact with said two cylinders in each printing station ing.

Each printing station also has a cylinder 9
It includes a printhead 96 which is supported in close proximity to the cylindrical surface of the cylinder 92 by a lead screw 98 which is rotatably mounted to the machine frame so as to be parallel to the members 2, 94. The lead screw 98 can be bidirectionally rotated by a reversible step motor 102 that receives a drive signal from the controller 15.

The print head, print cylinder, and print controller are described in the inventor's patent No. 4,792,860 of the present invention.
No. (the contents of which are incorporated herein by reference) or the form described in the above-mentioned patent application filed by the same inventor.

In operation of the apparatus, in response to the data stream it receives, controller 15 issues a print signal to print head 96 to cause the relevant print cylinder corresponding to the primary color component or color separation of the original document or image. An electronic image is written on 92, one image at a time as the print cylinder 92 rotates. The image written on each print cylinder 92 is dyed by applying electrostatic thermoplastic ink to the cylinder surface from an ink source 106 at an ink station. As described in the inventor patents and patent applications of the present invention, the ink adheres only to the surface of the cylinder 92 charged by the print head 96. When the inked portion of the rotating cylinder 92 encounters the support S passing through the corresponding inking station, the ink is transferred to the support. As with most printing machines, the position of the image written on each printing cylinder 92 is such that the position of the support S on the support carrier is such that the image printed on the support is in the correct position on the support. It is arranged in a certain relationship with.

Still referring to FIG. 1, when printing using an electronic print head 96 similar to that described in the earlier patent application by the inventor of the present invention, the print head is always fixed. ing. However, in accordance with the present invention, the printhead is moveable transversely over the lead screw 98, which may result in a belt loop 10 that may be caused by a delay or advance in the servo circuit that adjusts the belt position.
Eliminates the residual transverse displacement of. More specifically, the signal from the detector 58 for monitoring the belt position and the second detector 5
A signal from 8 a is used together, the print head 9
6 is moved to compensate the deviation as described above. Reference position the belt loop 10 is selected, for example, deviates from the machine center line, the controller 15 receives the output signal from the detector 58 and 58 a, and calculates the vector movement of the belt 10 in the direction of movement, the lead screw An appropriate drive signal is sent to the step motor 102 that rotates 98. Rotation of the lead screw moves the corresponding position of the print head 96 transversely to reposition electronic image dots being written on the print cylinder 92 transversely to compensate for belt misalignment. At the same time, the timing of writing the image dots on the cylinder 92 by the print head 96 is adjusted to compensate for the speed fluctuation of the belt loop 10 when it is detected by the clock track detector 54.

During operation of the apparatus, the support S is continuous at the inlet end of the belt loop 10 in the upper belt extension section 10.
a and is secured to the upper belt extension by the high friction film 38 on the belt and the electrostatic mounting grid 32. Controller 15 is to come to the center of each support fed printing station 16 a to adjust the print work that is being advanced by 16 c in the image properly support onto the belt loop. When the support member approaches the first printing station 16 a, controller 15 adjusts the print head 96 of the printing station 16 a, the print head is to write electronic images on the printing cylinder 92 in the station, The image is a cyan ink source 106
Ink is granted, and the support reaches the printing station 16 a, the image that has been inked passes between cylinders 92 and 94 of the station is to be transferred to the support by. During this time, the controller 15
Receives signals from the detectors 54, 58 and 58 a indicating the lengthwise position and a transverse position of the upper belt extending portion 10 a. The controller uses this information to determine whether the image being written on the print cylinder 92 should be moved axially or circumferentially on the cylinder to compensate for belt position and velocity variations. decide. If the belt is deviated in the transverse direction, the controller calculates the amount of deviation and the belt position in the longitudinal direction and sends a drive signal to the step motor 102 to move the print head 96 in one direction or the other direction. Compensate for the deviation.

Similarly, when a change in belt speed is detected, the controller 15 adjusts the timing of the writing operation being performed by the print head to adjust the circumferential position of the image dots on the print cylinder 92. To compensate for belt speed changes. Therefore, as the support S passes through the first printing station 16 a , the belt need not be between the time the support is placed on the belt and the time the support is processed by the printing station 16 a. However, the cyan image is printed at an appropriate printing position on the support S.

Similarly, the support is printing station 16a.
As it progresses from the print station 16b to the print station 16b , the device continues to monitor the belt movement to
By adjusting the position and / or timing of the print head 96 at b, the print head 96 of the print station will be in position and timing by the time a particular print dot or pixel on the support reaches the print station 16b. is in a state of being already regulated have, printhead write magenta image dot corresponding to the appropriate position of the printing cylinder 92 of the printing station 16 b, on the support S when the cyan printing dots has reached the printing station 16 b The magenta image dot is superimposed on the cyan image dot.

The deviation of the belt when it wanders can be predicted by the inherent adjustment periodicity of the servo device that continuously adjusts the belt as it moves. Accordingly, each write head 96 associated with the associated print cylinder 92 is continuously adjusted in anticipation of the arrival of print dots so that the next dot is always exactly overlaid on the previous dot. It is possible. The controller 15 is able to calculate the speed of the belt, the distance traveled by each print dot and the position of the dot being written on the print cylinder so that the two are simultaneously concentrated at the correct position on the support. . That is, the write head continuously moves microscopically and moves in the transverse direction when each signal is placed on each print cylinder according to the calculation result from the controller.

For example, the belt stretching section 10a is provided with the support S.
Print from the printing station 16 a station 16 b
Should the sheet shift to the left during conveyance, such a shift is detected by the detector 58 and transmitted to the controller 15. The controller knows the position of the belt stretching portion 10 a from the signals supplied by the detectors 54, 58 and 58 a, corresponding is superimposed onto the printed print dot P _c of the support in the printing station 16 a Calculate how much the print head 96 of the print station 16b must be moved to the left in order to write the magenta image dot I _m on the cylinder 92. That is, without such a correction, the printing station 16 b is placed on the cylinder 9 so that it is on the right side of the printing dot P _c on the support S.
Image dot I _m will be printed on 2. However, if with a present invention, the print head 96 is moved to the left by the offset and the same amount of belt, an image dot I _m that matches the print dot P _c is superimposed on the printing dots P _c.

This process is carried out continuously as the support passes through each printing station of the printing machine, and when the support leaves the printing machine, all print dots are properly registered on the support. In this state, three-color printing is done on the support.

The "predictive positioning" of the present invention
Utilizing the principle of "active positioning", the electrostatic transport of the present invention can significantly exceed the currently achievable print registration accuracy of only about ± 100 microns in the area of color printing. Of.

The belt-type transport device described above with an electrostatic mounting grid can also facilitate double-sided printing of the support. For this purpose, two such conveyors are arranged in series so that the upper extension of one belt loop is flush with the lower extension of the other belt loop, as shown in FIG. Left-handed conveyor belt loop 10
A sheet of support S placed on it is conveyed by the belt loop through a first printing press which prints on the upper side of the support as explained above. At the end of the belt loop, this support is handed over to a right-handed carrier, the belt loop 10 'of which comprises an electrostatic mounting grid similar to grid 32 in FIGS. However, in the latter transport device, the grid is activated in the lower zone of the belt loop and the support is hung from the lower extension of the belt loop and transported through a second printing machine to provide support. The print is made on the other side of the body.
The support can be adapted to be delivered to a suitable tilting tray T at the exit of the transport device on the right.

Of course, an openable electrostatic mounting grid could also be incorporated into the cylindrical surface of the paper drum or cylinder to lift the support from the drum or cylinder in a manner similar to that described for belt loop 10 above. It is also possible to release it.

Reference is now made to FIG. 6 which shows a reciprocating or moving bed type carrier incorporating the electrostatic mounting grid of the present invention. This conveying apparatus, electrostatic hold grating 118 a and 11
It includes a pair of spaced apart parallel stationary side plates 116 a and 116 b have incorporating 8 b. Reciprocate the plate 122 is positioned slidably provided with a grating 124 mounted electrostatic similarly between the side plates 116 a and 116 b. The plate 122 is reciprocated back and forth in parallel with the plates 16 a and 16 b by a linear actuator 126 having an armature 126 a connected to one end of the plate 122. Fixed installation grid 1
18 a and 118 b are electrically connected in parallel to the voltage source V ₁ via one terminal of the double throw switch 128. The other terminal of the switch 128 is a movable plate 1.
On 22 the grid 124 is connected to the same voltage source. The actuator 126 is connected to the second voltage source V ₂ via the second switch 129, and the two switches 1
The positions of 28 and 129 are controlled by the relay coil 130.

[0061] When energized the actuator 126, armature to advance the plate 122 to the right, the power supply to the actuator is interrupted, the internal spring (not shown) is retracted the armature 126 a and the plate 122 Energize in place. The relay 130 is, for example, the controller 15
It is clear from FIG. 6 that when energized by the control signal from (FIG. 1), the switch 129 closes, thereby energizing the actuator and moving the plate 122 to the right to its advanced position. . At the same time, relay 13
0 activates switch 128 to connect electrostatic mounting grid 124 on moving plate 122 to voltage source V ₁ and electrostatic mounting grid 118 a on plates 116 a and 116 b.
And disconnects the 118 b and the voltage source. Therefore,
The support S placed on the carrier is the moving plate 12
It will be fixed to 2 and will be advanced together with the plate.

On the other hand, when the power supply to the relay 130 is cut off, the switch 129 is opened, so that the power supply to the actuator is cut off and the plate 122 is moved backward to the left or moved to a fixed position. At the same time, relay 1
30 moves switch 128 to the other position, disconnecting electrostatically mounted grid 124 from voltage source V ₁ and grid 118 a
And connecting 118 b to the voltage source. Therefore, when the plate 122 is retracted, the support S is fixed is released from the plate 122 to the plate 116 a and 116 b, will remain in its advanced position. When the movable plate 122 is subsequently reciprocated and the movable and fixed installation grids are opened and closed 180 degrees out of phase,
The support S will continue to advance to the right in FIG. Of course, it is also possible to devise a reciprocating type transport device that travels a shorter distance than a piezoelectric vibrator or bender is used to move the movable member or members of the transport device.

From the above, it is clear that the conveying apparatus of the present invention can convey and position documents and other articles along a fixed path with a high degree of accuracy.
Accordingly, the transport apparatus of the present invention can be used in a wide range of applications in which a series of operations needs to be performed at a specific position on a flat article of one type or another type.

Accordingly, it can be seen that the objects set forth above among the objects of the invention which have become apparent from the foregoing description are effectively achieved and that certain modifications can be made without departing from the scope of the invention. Therefore, all things included in the above description or shown in the accompanying drawings are made for the purpose of illustrating the present invention, and It was not made to limit.

It should also be understood that the appended claims are intended to cover all of the general and specific features of the invention described herein.

[Brief description of drawings]

FIG. 1 is an isometric view of a color printing machine incorporating a transport apparatus made in accordance with the present invention.

FIG. 2 is an enlarged partial plan view of a conveyor belt of the conveyor of FIG.

3 is a partial cross-sectional view of a variable geometry guide roller used in the transport device of FIG.

4 is a cross-sectional view taken along the line 3A-3A of FIG.

FIG. 5 is a diagram of a belt-type transport device for enabling double-sided printing.

FIG. 6 is a similar view of a reciprocating transfer device incorporating the present invention.

[Explanation of symbols]

10 Carrier 32 Electrostatic Installation Grid 3
4, 36 electrodes 42 power supply 46 photoelectric resistor 48
Light shield

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technology display area // B65H 5/02 T

Claims (28)

[Claims] 1. A carrier having a surface, a row of first conductors extending below the surface substantially parallel to each other, and a second row extending below the surface substantially parallel to the first conductor. A row of conductors, each second conductor being closely spaced from the first conductor to define a narrow gap between the second conductor and the first conductor; Means for applying a constant potential difference between the column and the first conductor and the second conductor to generate an electrostatic field in the gap capable of attracting and holding the support on the surface of the carrier. And adjusting the potential difference applying means to adjust a portion of the surface of the carrier body where a certain potential difference is applied only to the conductor selected from the first conductor and the second conductor to hold the support. And a control means for controlling the transport apparatus. 2. The carrier device according to claim 1, wherein the carrier is a flexible belt. 3. The transfer device according to claim 1, wherein the transfer body is a rotary cylinder. 4. The first and second members, wherein the carrier is movable in parallel to each other in a substantially common plane, and means for relatively moving the members, A second member is provided with the first conductor row and the second conductor row, respectively, and the control means, when the two members relatively move in one direction, one member of the member Between the first and second electrodes of, and between the first and second electrodes of the other member when the two members are moving in opposite directions. The transport device according to claim 1, wherein adjustment is performed so that a potential difference is applied. 5. The control means includes a switch in the circuit between the potential difference applying means and each of the conductors of at least one row of the conductor row, and an activation means for selectively activating the switch. The carrier device according to claim 1, wherein the carrier device is a carrier. 6. The activating means is arranged in one or more fixed zones along a path of the carrier facing the switch on the carrier, and the switch is provided when the carrier moves. The transport device according to claim 5, wherein the transport device is activated when the switch is positioned in the zone. 7. A support, a pair of rollers rotatably attached to the support, spaced apart from each other in parallel, engaging around the rollers and spanning between the rollers to form an upper portion. Forming a belt stretching portion and a lower belt stretching portion, further, a belt loop having an outer surface, a means for rotating at least one of the rollers to move the upper belt stretching portion in a selected longitudinal direction, the belt An electrostatic hold-down grid incorporated in a loop and including first and second electrode rows, and a predetermined potential difference applied to the first and second electrode rows, the belt loop A voltage source for generating an electrostatic field of sufficient strength from the outer surface of the belt loop to attract and hold the support introduced to the outer surface of the belt loop. Conveying apparatus according to claim. 8. The strength of the electrostatic field generated in the belt loop is discharged from the outlet of the belt loop without the support introduced into the outer surface of the belt loop being conveyed and rotating downward. The transport device according to claim 7, wherein the transport device is related to the weight and the rigidity of the support. 9. Isolating selected electrodes of the first electrode row and / or second electrode row from the voltage source so that only selected portions of the belt loop pull and hold the support. The transport device according to claim 7, further comprising: 10. The isolation means comprises a switch connected between the voltage source and each electrode of at least one of the electrode arrays, the switch being located at a selected station along the belt loop path. The transport device according to claim 9, further comprising means for opening the switch when the transport device is opened. 11. The carrier device according to claim 10, wherein the switch is a photoelectric switch that opens when light is blocked at the station. 12. The high friction coating is further included on the outer surface of the belt loop.
The transport device according to. 13. The conveying device according to claim 12, wherein the coating film is neoprene rubber or silicone rubber. 14. A second pair of rollers similar to the first pair, and a second pair of rollers similar to the first belt loop and engaged about the second pair of rollers. The belt loop and one of the two pairs of rollers relative to each other in series so that the upper extension of one of the belt loops is substantially flush with the lower extension of the other belt loop. 8. The conveying device according to claim 7, further comprising: a means for delivering a support body having one side exposed on the upper side to the other belt loop so that the other side is exposed. 15. Monitoring means for monitoring the transverse position of the belt loop with respect to a selected position and for producing an output signal indicative of the monitoring result; and in response to the control signal, the belt loop is traversed in the transverse direction. Further comprising moving means for moving and servo means for sending a control signal to said moving means in response to said output signal to cause said moving means to maintain said belt loop at said selected position. The transport device according to claim 7, wherein: 16. The monitoring means is positioned adjacent to the belt position mark on the belt loop and adjacent to the belt loop to detect the mark and to generate the output signal indicating the detection result. The transport device according to claim 15, further comprising a detector. 17. The indicia comprises a plurality of closely spaced parallel lines extending longitudinally on the belt loop, and the detector together with the lines provides an interference pattern. The transport device according to claim 16, wherein the transport device is a detector of an optical grating type to be created. 18. A print head for writing an image on a support held on the outer surface of the belt loop, and positioning means for movably positioning the print head opposite the outer surface of the belt loop. Moving means for moving the print head in a transverse direction perpendicular to the selected direction in response to a head control signal, and a head control signal for sending the print head to the moving means in response to the output signal. 17. The transport apparatus according to claim 16, further comprising second servo means for moving in the transverse direction to compensate for the transverse movement of the belt loop from the selected position. 19. A timing mark engraved on the belt loop, a sensor that senses the timing mark and generates a timing signal in response to the timing mark, and responds to the timing signal to advance writing by the print head. 19. The transport apparatus according to claim 18, further comprising: print control means for compensating for movement changes in the belt loop in the selected direction. 20. The monitoring means opposes the belt loop at a position spaced from the first detector that detects the transverse position of the mark and generates a second output signal indicating the result. 7. A second detector positioned in position, the second servo means generating a head control signal to the moving means in response to the second output signal. 19. The transfer device according to item 19. 21. The transport device according to claim 15, wherein the moving means includes means for changing the conicity of one of the rollers. 22. The one of the rollers has a cylindrical central body, a pair of variable-diameter extension members at both ends of the central body, an elastic cylindrical sleeve surrounding the central body and the extension member, and the control. 22. The transport apparatus according to claim 21, further comprising means for changing a diameter of the extension member in response to a signal. 23. A support, a pair of rollers rotatably mounted on the support, spaced apart from each other in parallel, engaging around the rollers and spanning between the rollers, A belt loop having a belt stretching portion and a lower belt stretching portion, and further having a belt loop having an outer surface; and a means for rotating at least one of the rollers to move the upper belt stretching portion in a selected longitudinal direction, Means for monitoring the transverse position of the belt loop with respect to position and producing an output signal indicative of the result; a print head for writing an image on a support carried on the outer surface of the belt loop; Positioning means for movably positioning the head opposite the outer surface of the belt loop, and the selected longitudinal direction in response to a head control signal. Moving means for moving the print head in a transverse direction perpendicular to, and in response to the output signal, sending a head control signal to the moving means for moving the print head in the transverse direction to move the belt loop. A conveyance device comprising: servo means for compensating a transverse movement from the selected position. 24. A timing mark engraved on the belt loop, a sensor that senses the timing mark and generates a timing signal in response to the timing mark, and in response to the timing signal, writing by the print head proceeds or Print control means for delaying and compensating for movement changes of the belt loop in the selected direction.
The transport device according to item 3. 25. The monitoring device detects a belt positioning mark on the belt and a transverse position of the mark at the position, and generates the output signal and a second output signal indicating a result of the detection. A pair of detectors positioned opposite the belt loop at spaced positions, and the second servo means is responsive to the output signal and the second output signal, The transport apparatus according to claim 24, wherein the head control signal is sent to the moving means. 26. A conveyor for transporting articles, means for moving the conveyor in a selected longitudinal direction, means for fixing the article position on the conveyor, and article positioning for facing each of the conveyors. First and second spaced apart workstations including means; moving means for moving the article processing means in a transverse direction perpendicular to the selected longitudinal direction in response to a control signal; Detecting means for monitoring the transverse position with respect to the selected fixed position and generating an output signal in response to the monitoring result; and transmitting a control signal to the moving means in response to the output signal, And moving the article handling means in a second workstation to fix the article on the conveyor after the article is secured to the conveyor. And a servo means for compensating the transverse movement from the selected position. 27. A series of longitudinal timing marks engraved on the conveyor, sensing means for sensing the timing marks and generating a timing signal in response to the sensing result, and responsive to the timing signal. A control means for advancing or delaying the operation of the article processing means so as to compensate for the movement change of the conveyor in the longitudinal direction after the article is fixed to the conveyor. The transport device according to claim 26. 28. The monitoring means is also spaced from the first detector means for detecting a transverse position of the conveyor with respect to the fixed position and producing a second output signal indicative of the detection result. A second detector positioned at a position opposite the conveyor, and the second servo means also provides the control signal to the moving means in response to the second output signal. 27. The transport device according to claim 26, wherein: