This invention relates to, in one embodiment, a conveying apparatus comprised of a conveying section and a supporting section designed to transport printing plates or other media from a first location to a second location. The apparatus is adapted to transport media regardless of the size of the media. Additionally, the apparatus is configured to receive a media from an imaging device that is operating at a first speed, transport the media with a transporter operating at a second speed, and deliver the media to a processor operating at a third speed. The first speed, second speed, and third speed, need not be the same speed.
The present invention relates generally to a media transportation apparatus for moving printing media from a first location to a second location. The media transportation apparatus of the present invention permits media of various sizes to be moved without the need for expensive and costly equipment.
Current printing technology utilizes a variety of printing methodologies and assemblies. One such printing system is the so-called “Computer-to-Plate” (CTP) system. Reference may be had to U.S. Pat. No. 6,684,783 to Salvestro (Method for imaging a media sleeve on a computer-to-plate imaging machine); U.S. Pat. Nos. 6,662,723; 6,526,886; 6,523,473; 6,523,472; 6,457,413; all to Loccufier (Computer-to-plate by ink jet); U.S. Pat. Nos. 5,992,324 and 5,738,014; both to Rombult (Method and apparatus for making lithographic printing plates in an automated computer to plate imaging system); and the like. The content of each of the aforementioned patents is hereby incorporated by reference into this specification.
A Computer-to-Plate (CTP) system uses a CTP device to imprint a digital image onto a plate. This plate (i.e. media) is conveyed by a transportation apparatus from the CTP device to a processing device. The processing device develops the plate in preparation for printing.
Existing transportation apparatuses suffer from a number of limitations. Prior art transportation devices cannot easily accommodate plates of various sizes. Existing transporters are also prone to jamming. Generally, there are five types of transportation devices: Single wide belt transporters, Plurality of thin belt devices; Gravity rolling devices; Gripping devices, and Switchable devices.
Single wide belt transporters use a single wide conveyor belt to move the printing media (i.e. plate) from the CTP device to the processor device. Such devices are limited by the width of the belt itself. The transporter is unable to accommodate plates that are wider than the belt. Attempts have been made to use extremely wide belts, but such attempts have caused additional problems. Wider belts are difficult to control and thus require additional controlling mechanisms that add to the equipment costs of such assemblies. For example, additional mechanisms are often needed to ensure the belt properly tracks. Wider belts also require higher tension to prevent such a belt from slipping. These high tension belts, in turn, necessitate the use of costly, high torque motors. This higher tension necessitates the use of a more powerful and more expensive motor to drive the wide belt. Wider belts also increase the frictional force that is applied to the printing plate. This additional frictional force often prematurely pulls the plate from the CTP device before the image can be properly transferred to the plate. Such improper handling results in unacceptable image defects in the plate. Additionally, reconfiguration of the device for use with wider plates is difficult—such a reconfiguration requires replacing a substantial amount of the equipment.
Some transporter devices use a plurality of thin belt devices in an attempt to address the issues caused by the single wide belt transporters. However, such a thin belt design gives rise to other problems. The use of multiple thin belts leaves gaps between the belts. If a plate should have a width such that it falls within such a gap, the plates have been known to become lodged between the belt and the pulley that drives the belt, thus producing a jam. It would therefore be advantageous to provide a device that ensures the end of a plate will not rest in such a gap. Additionally, the more belts that are used, the more difficult it becomes to service such belts.
Gravity rolling transporters use inclined rollers to transport a plate from the CTP device to the processing device. However, the speed a plate travels down the incline is difficult to control and depends upon the weight, and thus the size, of the plate. Larger plates travel down the incline substantially faster than smaller (lighter) plates. Some degree of control can be achieved by altering the angle of the incline, however, such control is minimal. The small plates typically require a very steep angle to be properly transported, thus producing a rapid decent. During such a rapid decent, the plate may not fall to the processing device properly. In such an event, user intervention is required to rectify the situation.
Gripping transporter devices engage a plate at a first location, transport the plate to a second location, and thereafter disengage from the plate. One such gripping transporter is disclosed in U.S. Pat. No. 5,465,955 to Krupica (Method and Apparatus for an External Media Buffer), the content of which is hereby incorporated by reference into this specification. The operating speed of such gripping transports must exactly match the speed of the CTP device to which they are attached, or the media may not be properly transported. Moreover, the complexity of such gripping transporters causes them to have low reliability and increased equipment costs relative to other transporters.
Switchable transporter devices have attempted to address these shortcomings, but none of these devices has proven entirely satisfactory. Switchable devices are reconfigured by the user to permit the transporter to accept a media at a first speed, transport the media at a second speed, and deliver the media at a third speed. Such devices are rather complex, and this complexity often results in processing complications and low reliability. Additionally, such devices require user intervention to reconfigure the device for different speeds. The complex nature of the switchable transporter also results in higher equipment costs. One example of a switchable transporter is disclosed in U.S. Pat. No. 4,835,574 to Ohi (Automatic Photosensitive Material Conveying Apparatus), the contents of which are incorporated by reference into this specification.
The prior art considered of some importance to this application includes U.S. Pat. Nos. 2,682,208 to Monroe (Carton Converting Machine); 3,117,333 to Murray (Aperture Card Cleaner); 3,410,183 to Sarka (Material Processing Method and Apparatus); 3,935,941 to Keck (Adjustable belt conveyor); 3,938,674 to Kroeze (Method and apparatus for stacking paperboard blanks); 4,241,910 to Matsuo (Sheet delivering apparatus); 4,666,140 to Godlewski (Self-contained serially arranged plural section conveyor); 4,773,638 to Koutoudis (Deposit drawer for a document processing equipment for the deposit of documents having different sizes); 4,805,890 to Martin (Sheet stacking machine); 4,835,574 to Ohi (Automatic photosensitive material conveying apparatus); 4,930,765 to Russel (Sheet collection mechanism for stacking long and short sheets); 5,054,760 to Reist (Apparatus for conveying flat products); 5,087,026 to Wyer (Sheet conveying apparatus for conveying variable length sheets to a stack having a selectively positionable transport roller); 5,277,297 to Tolson (Controllable length conveyor); 5,465,955 to Krupica (Method and apparatus for an external media buffer); 5,529,081 to Kappler (Apparatus for the treatment of board-like articles); 5,609,335 to Parker (High capacity stacker/separating device); 5,669,604 to Hansen (System for accelerating and transferring imbricated printed products to a gripping chain); 5,685,539 to Janatka (Disk transport for paper sheets); 5,692,745 to Neifert (Belt-driven document accumulator having belt-dampening table and side guides); 5,915,686 to Neifert (Document accumulator having rotating assemblies for ramp adjustment); 5,954,473 to Folsom (Readily adjustable cut sheet stacker); and 6,575,457 to Bakoledis (Variable length sheet feeding mechanism). The content of each of the aforementioned patents is hereby incorporated by reference into this specification.
It is an object of this invention to provide a media transportation apparatus capable of transporting media of various sizes that is an improvement over the prior art devices.
It is an object of this invention to provide an uncomplicated, inexpensive media transportation apparatus capable of receiving a media at a first speed, transporting the media at a second speed, and delivering the media at a third speed, wherein the first, second and third speed are not necessarily synchronized.
In accordance with the present invention, there is provided a media transportation apparatus that is comprised of a conveying section and a supporting section. The conveying section is comprised of a motor and a first timing belt, wherein operation of the motor causes the first timing belt to travel in a first direction at a belt speed. The supporting section is comprised of rollers configured to roll in the same first direction. The first timing belt has a belt surface and the rollers have a rolling surface, such that the belt surface and the rolling surface are substantially coplanar with respect to one another. In some embodiments of the present invent, a second timing belt is present.
The invention is capable of transporting media, irregardless of the size of the media. Additionally, the apparatus is configured to receive a media from an imaging device that is operating at a first speed, transport the media with a transporter operating at a second speed, and deliver the media to a processor operating at a third speed. The first speed, second speed, and third speed, need not be the same speed.
The techniques described herein are advantageous because they are simple and inexpensive compared to prior art approaches. Additionally, the techniques taught herein are more flexible than prior art techniques and can easily be adapted to any number of printing plate sizes without the need for complex machinery.
The invention will be described by reference to the following drawings, in which like numerals refer to like elements, and in which:
The present invention will be described in connection with a preferred embodiment, however, it will be understood that there is no intent to limit the invention to the embodiment described. On the contrary, the intent is to cover all alternatives, modifications, and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.
For a general understanding of the present invention, reference is made to the drawings. In the drawings, like reference numerals have been used throughout to designate identical elements.
Referring now to
In the embodiment depicted in
In one embodiment of the present invention, timing belts 106 and 108 are toothed timing belts. Such toothed belts are known to those skilled in the art. Reference may be had to U.S. Pat. No. 5,599,246 to Fujiwara (Toothed Belt); U.S. Pat. No. 6,926,633 to Di Cesare (Toothed Belt); and the like. The content of each of the aforementioned patents is hereby incorporated by reference into this specification. In one embodiment of the invention, the teeth of the toothed belt are disposed on a toothed surface of the belt and the opposing side of the belt is a non-toothed surface. The toothed surface is contiguous with cover 116 such that motor 110 contacts the toothed surface. In this manner, the motor engages the toothed surface and drives the timing belt(s). Such a toothed configuration reduces the belt tension, thus allowing the use of low torque motors, while still permitting translation of the belt. The weight of the media on the non-toothed surface of the timing belts 106 and 108 causes the timing belt to become depressed, and thereby rest on the top surface of cover 116. Cover 116, therefore, functions to support the media and ensures the media remains parallel to plane 120.
It is preferable that the small media 200 have a width greater than the belt distance between the two timing belts 108 and 106. In one embodiment, the media, such as larger media 202, has a width that is substantially greater than smaller width 204. If media with a width substantially greater than smaller width 204 is used, such larger media 202 will come into contact with rollers 114, and be supported by such rollers. In one embodiment, the media varies in size from about 23 centimeters wide and 23 centimeters long to about 82 centimeters wide and about 114 centimeters long. In another embodiment the area of the media varies from about 520 square centimeters to about 9,350 square centimeters. Transporter 100 is adapted to transport media which is in a landscape orientation, i.e. wider than it is long, such as media 200 and media 202. Transporter 100 is also adapted to transport portrait media, i.e. longer than it is wide, such as media 201.
As can be seen in
Referring again to
In one process of the invention, CTP device 400 presents the media 408 to the transporter 100 at an imaging speed at first location 401. Thereafter, transporter 100 accepts media 408 onto the belt surface of belts 106 and 108 (see
The non-toothed surface of timing belts 106 and 108 provides a relatively low friction surface such that the media remains on the belts without slipping, but the friction is not so high that the belts prematurely withdraws the media from CTP device 400. Similarly, the relatively low friction surface of timing belt 106 and 108 does not substantially resist the pulling action of drive force enhancer 308 and pressure roller 404. In one embodiment, drive force enhancer 308 is comprised of a clutch bearing 500 (see
Clutch bearing 500 permits the drive force enhancer 308 to rotate at a speed other than the speed of the second timing belt 108. In this manner, the imaging speed of the imager, the belt speed of the transporter and the processing speed of the processor need not be synchronized. In one embodiment, first and second timing belts 106 and 108 are traveling at a belt speed and the drive force enhancer 308 and pressure roller 404 are rotating at a drive force enhancer speed, wherein the drive force enhancer speed is greater than the belt speed. For example, in one embodiment, the belt speed is from about 9 centimeters per minute to about 200 centimeters per minute and the drive force enhancer is greater than such belt speed. In one embodiment, the drive force enhancer speed varies from about 9 centimeters per minute to about 200 centimeters per minute. In one embodiment, the drive force enhancer speed varies such that it may travel as slowly as the belt speed or as quickly as the processor speed. The speed of the drive force enhancer is determined by measuring the amount of time necessary to move a plate with a certain length from one side of the enhancer to the other side of the enhancer. For example, if a media were 5 centimeters long and it took the drive force enhancer 0.05 minutes to move such media through the enhancer, then such an enhancer would be operating at a drive force enhancer speed of 100 centimeters per minute.
The present invention permits the CTP device 400 to operate at an imaging speed, the processor device 402 to operate at a processing speed, and the transporter 100 to operate at a belt speed, wherein the aforementioned speeds are not necessarily equal. As would be apparent to one skilled in the art, the imaging speed of CTP devices 400 depends upon the resolution of the plate being produced. For example, higher resolution plates require greater imaging times, thus the imaging speed is relatively slow. In one embodiment of the invention, transporter 100 is operating at a belt speed that is greater than the imaging speed of CTP device 400. Likewise, the processing speed of processor device 402 is not necessarily equal to the belt speed of transporter 100. In one embodiment, the processing speed is greater than the belt speed. For example, in one embodiment, as the plate is being presented by CTP device 400 to transporter 100 at an imaging speed which is less than the belt speed, the low friction surface of the timing belts will not pull the media from device 400 until such time as device 400 releases the plate. Once released, the media moves at the belt speed toward processor device 402 and presents the media to drive force enhancer 308. Drive force enhancer 308 grips the media and forcefully presents it to processor device 402, thus proactively pushing the media into receiving rollers 406. As would be know by those skilled in the art, devices such as processor device 402 typically require the media be partially disposed between the receiving rollers 406 by applying substantial force to the media. Once the media is partially disposed between receiving rollers 406, the rotation of such rollers pulls the media into the processor device 402. Nevertheless, an applied force is often needed so as to place the media in a position where the receiving rollers 406 can engage the media. Drive force enhancer 308 provides such a force. In the embodiment depicted, drive force enhancer 308 is a nip roller. As would be apparent to one skilled in the art, other suitable drive force enhancers may be used in place of a nip roller. Such alternative drive force enhancers are considered within the scope of this invention.
Once the receiving rollers 406 have engaged the media, the media is moving at a processing speed. In one embodiment, the processing speed is greater than the belt speed. In such an embodiment, clutch bearing 500 allows the drive force enhancer to rotate at a speed other than the belt speed (i.e. at the processing speed). Thus, the one-way clutch bearing 500 releases the media to processor device 402 without resisting the pull of receiving rollers 406.
It is therefore, apparent that there has been provided, in accordance with the present invention, a method and apparatus for transporting media from a first location to a second location. While this invention has been described in conjunction with preferred embodiments thereof, it is evident that many alternatives, modifications, and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.