Abstract:
An apparatus for transporting web-shaped recording media through an electrographic printer or copier has a support member which supports driving and guiding elements. The support is pivotally mounted in the housing via a support shaft. The recording medium is transported by friction by a drive roller mounted on the support, the recording medium being pressed against the toner carrier by a pressing member. The supporting shaft and the drive roller run in a coaxial manner.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is directed to a means for transporting a web-shaped recording medium in an electrographic printer or copier device. 
     2. Description of the Related Art 
     In printer devices of this species, the recording media are transported along a printing station and printed thereat. As needed, the recording medium is thereby composed of paper, of plastic film material or of other materials as well. The recording medium is printed over a specific width in the transfer printing station of such devices. 
     Dependent on the embodiment of the printer device, single sheets, roll goods with margin perforation or roll goods without margin perforation can be printed. Whereas paper with lateral holes for transport and position monitoring of the paper is employed in many applications, paper grades that exhibit no such margin perforation but are nonetheless fabricated as roll goods or fanfold paper are also increasingly employed. 
     Published International Patent Application WO 95/19929 A1 discloses a printer that can process roll paper without margin perforation as well as with margin perforation. A first seating edge, which prescribes the lateral position of the paper, as well as stabilization rollers, an under-pressure brake and a roller arrangement with a loop-drawing means are provided in this printer for the exact guidance. 
     Given printers of this type, there is often the problem that the paper transport unit must be disassembled for service purposes. For example, it regularly occurs that what is referred to as a corotron wire breaks during printing operation and a new corotron wire must be introduced. When such a service instance occurs during printing operation, then it is desirable to return the paper into the same position after the service action that it was in previously. Otherwise, a relatively complicated procedure must be started in order to restart the printing operation, whereby it is usually necessary to reprint various pages. Not only does excess printed matter (maculature) arise as a result thereof, additional outlay for sorting the reprinted paper out is also incurred. 
     European Patent document EP 0 399 287 A2 discloses a device for transporting a web-shaped recording medium in an electrographic printer or copier device. The carrier shaft and the drum for transporting the web-shaped material are arranged essentially coaxially. 
     German Patent document DE 42 14 126 A1 discloses an apparatus wherein a carrier is seated pivotable around a drum axis. The carrier is pivotable together with the drive drum and a contact pressure drum. 
     U.S. Pat. No. 4,642,661 discloses a transport mechanism for a web-shaped recording medium in a printer device, whereby transport and contact pressure elements of a pin feed wheel or, respectively, tractor drive are arranged at a carrier. The transport and contact pressure elements can be swivelled around an axis together with the carrier, whereby the drive shaft of the tractor proceeds concentrically relative to the swivelling axis of the carrier. 
     SUMMARY OF THE INVENTION 
     It is an object of the present invention to provide a means for transporting a web-shaped recording medium in an electrographic printer or copier device with which a positionally exact printing is also retained in the region of the transport unit after a service call. 
     This object is achieved by the apparatus described with the features of a carrier carrying a plurality of drive and guide elements, the carrier being pivotably seated at the housing of the printer or copier device via a carrier shaft and being capable of being pivoted back and forth between a working position and a service position; a drive drum seated at the carrier, the recording medium being transported by the drive drum with friction and the drum proceeding coaxially with the carrier shaft; contact pressure means with which the recording medium is pressed against a toner transfer means, particularly against a photoconductor drum, in the transfer printing area of the printer or copier device; and a means with which a retaining moment can be transmitted onto the recording medium during the pivot motion for stabilizing the position of the recording medium relative to the drive drum, and by the method for transporting a web shaped recording medium in an electrographic printer or copier device, including a carrier carrying a plurality of drive and guide elements is provided, the carrier being pivotably seated at the housing of the priner or copier device via a carrier shaft and being capable of being pivoted back and forth between a working position and a service psoition; a drive drum seated at the carrier is provided, the recording medium being transported by the drive drum with friction and the drum proceeding coaxially with the carrier shaft; contact pressure means with which the recording medium is pressed against a toner transfer means, particularly against a photoconductor drum, in the transfer printing area of the printer or copier device; are provided; and a retaining moment is transmitted onto the recording medium during the pivot motion for stabilizing the position of the recording medium relative to the drive drum. Advantageous exemplary embodiments of the invention provide a lock mechanism with which the means can be locked in a working position at the housing of the printer or copier device; and means for power support with which the means can be brought into a service position in the unlocked condition. In a preferred embodiment, the means for power support comprise a gas compression spring. The gas compression spring is rotatably seated at the carrier at a first bearing point and at a second bearing point at a bearing block that is rigidly connected to the device housing. The drive drum is driven by a stepping motor, whereby the stepping motor is under power for exerting the retaining moment while the means is being pivoted from a working position into a service position and back into the working position. In one embodiment, the stepping motor is mounted at the carrier. A first adjustable detent is provided at the bearing block for adjustment of the means relative to the device housing along a first direction and a second adjustable detent is provided for adjustment of the means relative to the device housing along a second direction. The drive drum may interact with counter-pressure rollers that press against the drive drum with an adjustable spring power. Preferably, the drive drum is seated on the carrier shaft. 
     Inventively, the means for transporting a web-shaped recording medium in an electrographic printer or copier device comprises a carrier, which is pivotably seated via a carrier shaft at the housing of the printer or copier device, as well as a drive drum with which the recording medium is transported by friction. The drive drum is rotatably seated at the carrier. Further, pressing means are provided with which the recording medium is pressed against a toner transfer means in the transfer printing area of the printer or copier device. The carrier shaft and the drive drum proceed coaxially. As a result thereof, the position of the drive and guide elements mounted at the unit is retained relative to the paper given a pivot motion of the means or, respectively, of the drive unit. It is particularly provided for this purpose that the drive drum is driven by a stepping motor, whereby the stepping motor is placed under power while the means is pivoted from a working position into a service position and back into the working position. As a result thereof, a retaining moment is transmitted onto the paper web, this stabilizing the relative paper position during the pivot motions. 
     In particular, the drive drum is seated in the carrier shaft around which the unit is pivotable. As a result thereof, an especially exact allocation between paper and drive drum is assured during the swivel motion. 
     What the invention also effects is that the paper transport can be pivoted back and forth between a working position and a service position such that the relative position of the paper in the working position practically does not change with respect to device-fixed units such as the transfer printing station. 
     At least one adjustable detent is provided at a bearing block of the means for adjusting the drive unit relative to the housing of the printer. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are explained in greater detail below with reference to some Figures. 
     FIG. 1 is a side section view showing the paper running within an electrophotographic printer; 
     FIG. 2 guide elements for paper guidance; 
     FIG. 3 is a side view of an adjustment mechanism for the guide elements; 
     FIG. 4 is a cross sectional view of a paper transport means in the region of a transfer printing station; 
     FIG. 5 is a perspective view of the paper transport means; 
     FIG. 6 is a side view of the paper transport means in a pivoted-out condition; 
     FIG. 7 is a side view of the paper running in a parallel printer device; 
     FIG. 8 is a sectional drawing of the paper transport means; 
     FIG. 9 is a perspective view of the frame of the paper transport means; 
     FIG. 10 is a perspective view of a pin feed wheel sensor in the pivoted-in position; 
     FIG. 11 is a bottom perspective view of the pin feed wheel sensor in the pivoted-out condition; and 
     FIG. 12 is a section through a carrier shaft and a drive drum. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The paper transport means  1  shown in FIG. 1 conveys a paper web  6  from a paper supply  7  via a pre-centering means  8  and a drive unit  25  to a transfer printing station  5 . Thereat, the paper  6  accepts toner from the surface  19  of a photoconductor drum  2 , this toner having been applied onto the photoconductor drum  2  in the developer station  4 . The information that is thereby transferred corresponds to the latent image information written on the photoconductor drum  2  with the character generator  3 . 
     Overall, the paper transport corresponds to the arrangement disclosed by International Published Application WO 95/19229. The content thereof is herewith incorporated into the present specification by reference. 
     In the pre-centering means  8 , the paper web  6  is deflected by approximately 90° in the region of a detent plate  9 . This region forms a deflection path  24 . The paper web  6  is thereby conducted through between a roller arrangement  10 , whereby both the lower rollers  11  as well as the upper rollers  12  are placed at a slant relative to the paper transport direction A, so that the rollers  11 ,  12  exert a force perpendicular to the transport direction A onto the paper web  6  with their rotational movement. The paper web  6  is thereby pressed against the detent plate  9 , an adequately precise guidance being thus assured. The upper rollers  12  are, in particular, seated pivotable away from the common profile carrier  23 , so that a new paper web can be easily introduced between the rollers  11 ,  12 . 
     After the pre-centering in the deflection path  24 , the paper web  6  passes through a paper brake  13 . The braking effect thereof is based on an under-pressure with which the paper web  6  is drawn against an under-pressure chamber and thus decelerated. A tension is generated in the paper web  6  due to this braking. 
     Subsequently, the paper web  6  is supplied to a first loop-drawing means  15  by a deflection roller  14 . The loop-drawing means  15  is essentially composed of a movably seated roller  17  that is pulled by a spring  16  opposite the paper tension. A paper supply loop  22  arises as a result thereof. The paper web  6  wraps the roller  17  by approximately 180°, as a result whereof it is stabilized perpendicular to the transport direction A. The roller  17  is implemented as a lightweight structure. Its core, however, is composed of stiff material, for example of carbon fiber-reinforced plastic (CFK), in order to minimize elastic spring effects within the roller  17 . The loop-drawing means  15  and the under-pressure brake  13  form a regulating system that produces a constant tension of the paper web  6  from the under-pressure brake  13  to beyond the transfer printing station  5 . Magneto-resistive sensors  15   a  thereby sense the position of the roller  17 . During printings operations, the roller  17  is held as constantly as possible in a working position AP. The spring  16  has an exactly defined work area in a narrow range. The sensors  15   a  are arranged in this region around the working position AP in high-resolution fashion with eight measuring points. The under-pressure in the brake  13  is then set such that the roller positions deviate as little as possible from a rated, or target, position. 
     The roller  17  is in an upper insertion position EP for inserting a new paper web  6 . During a print stop (for example, when the drive unit  25  is pivoted away from the photoconductor drum), the roller  17  is in the pull-back position RP, whereby the loop  22  is larger than in the working position AP. When the paper web  6  tears, then the roller  17  moves into the lower position PP. One of the sensors  15   a  detects this event and forwards a corresponding error message to the system controller. 
     Following the loop-drawing means  15 , the paper web  6  is supplied to the drive unit  25 . Contact pressure rollers  20  press the paper web  6  against an drive drum  40  of the input side that drives the paper web  6  in the direction of the transfer printing station  5 . Before the paper web  6  reaches the transfer printing station, it is opto-electronically sensed with a paper width sensor  21 . Details of this sensor are described in FIG. 9 as well as in German Patent Document DE-U-297 23 879 (assignee&#39;s case number: 97 1101). 
     After the paper web  6  has passed through the transfer printing station  5 , it is supplied by the drive unit  25  to a second loop-drawing means  26  that is acted on by the tension of a spring  27  that is seated at a housing projection  28  of the printer housing  18 . After passing the second loop-drawing means  26 , the paper web  6  can be supplied to further units, for example a known fixing means wherein the toner image is fixed on the paper web  6 . 
     The exemplary embodiment that has just been described assumes that only one paper web  6  is transported through the transfer printing station. In a second exemplary embodiment, it can just as easily be provided that two paper webs  6  and  6   a  lying side-by-side are simultaneously transported through the transfer printing station  5 . The second paper web  6   a  would thereby be taken from a second paper supply  7   a . All paper guidance and paper transport elements as well as the transfer printing station and the photoconductor drum  2  would be adapted in view of their geometrical dimensions such that the two paper webs  6  and  6   a  can pass through the transfer printing station  5  side-by-side. The arrangement of the paper web and of the transport devices can thereby ensue as in Published International Application WO-A-96/03282. 
     The paper transport means is uniformly referenced with A in the Figure descriptions that now follow. The other reference characters have also been retained insofar as the same or, respectively, structurally identical elements are involved in the following Figures. 
     The detent plate  9  of the pre-centering means  8  is shown in greater detail in FIG. 2 a . It is firmly seated on a slide rail  32  that is seated displaceable along a corrugated profile plate  30 . To this end, the corrugated profile plate  30  is equipped with guide profiles  31  in the region of the slide rail  32 , so that the slide rail  32  is displaceable perpendicular to the direction C. The guide plate  9  also shifts together with the displacement of the slide rail  32 . The corrugated profile  30  is to be secured to the profile carrier  23  of the pre-centering means  8  with a suspension  29  as well as through screw openings  29   a . The guide plate  9  prescribes the lateral guidance of the paper web  6  in the entire paper run (FIG.  1 ). As disclosed by Published International Application WO-A-95/19929, braking device  13  and loops  22 , and  15  effect such a great stabilization of the paper web  6  that it no longer deviates from this laterally stable attitude up to the transfer printing area  5 . The guide plate  9  is thus the determinant lateral guidance element for the paper web  6  within the overall paper transport arrangement. 
     Both roll material having lateral margin perforations as well as roll material without lateral margin perforations can be transported with the described paper a transport because the transport ensues only with friction. What is of concern in the region of the transfer printing station  5  is that, dependent on the type of paper inserted (with/without margin perforations), the printable region of the paper comes to lie in a specific region of the photoconductor drum. Accordingly, it can be necessary to adapt the lateral guide plate  9  to the type of paper, i.e. to modify the position of the guide plate  9  perpendicular to the paper transport direction A. This can ensue by shifting the guide plate  9  with the slide rail  32  within the guide recess  31  along the direction B. FIG. 2 b  shows the view C of FIG. 2 a . The detent plate  9  is thereby displaceable along direction B together with the slide rail  32 . The lower ball bearing roller  11  is thereby also shifted, so that the relative position between ball bearing  11  and detent plate  9  is preserved. 
     The ball bearing roller  11  is inclined at an acute angle α of approximately 6° with respect to the direction B. What this effects is that paper that is moving in transport direction A experience a frictional force transversely relative to the transport direction ((in direction B). As a result thereof, the paper web is automatically guided along the detent plate  9 . 
     FIG. 3 shows a specific exemplary embodiment for a setting of two detent plates  9  and  9   a . The front detent plate  9  with the ball bearing roller  11  is thereby shifted as described in FIGS. 2 a  and  2   b . The displacement ensues with a lever  33  that attacks eccentrically at a sheave  35 . The offset between the mid-point  34  of the sheave  35  or, respectively, the transverse axis  37  and the lever  33  amounts to the spacing ‘a’. By moving the lever  33  along the axis  37 , the sheave  35  turns and entrains a rodding  38  with which the slide rail  32  moves along the axis  37 . The connecting lever  38  is likewise eccentrically mounted on the sheave  35  for this purpose. 
     A back guide plate  9   a  with slide rail  32   a  and ball bearing roller  11   a  is mounted at the opposite side of the sheave  35  practically mirror-inverted relative to the units  9 ,  32  and  11  such that the two detent plates  9  and  9   a  move oppositely when the lever  33  is moved along axis  37 . 
     The embodiment described in FIG. 3 for displacing the two detents  9  and  9   a  is employed when, according to FIG. 1, two paper webs  6  and  6   a  pass through the transfer printing station  5 . What is enabled as a result thereof is that the two paper webs are allocated center-symmetrically to the transfer printing station  5  and, thus, to the print image. In particular, it is provided to adjust the detents  9  and  9   a  by respectively half an inch, so that the entire width of the paper guidance channel is adjusted by one inch. The paper running edge that has been set can thereby be monitored with a sensor. Further, a malfunction message ensues in the control panel of the electronic device controller when the position of the paper web or, respectively, paper webs does not correspond to a predetermined rated value. 
     The adjustment means shown in FIG. 3 has two stable conditions. The two guide plates  9  and  9   a  have the spacing b in the first condition, and the spacing b+d in the second condition. The adjustment width d derives from the different papers employed. Paper with margin perforations is usually about one inch =2.56 cm wider than comparable paper without margin perforations. The width of the paper channel  39  must be set accordingly. The adjustment mechanism shown in FIG. 3 has two stable conditions. It is held under pre-stress for this purpose by a spring  36  rigidly mounted at the device. What the connecting rods  38  and  38   a  with appertaining slide rails  32  and  32   a  effect is that the sheave  35  can only turn within the range prescribed by the free range of motion of the slide rails  32  and  32   a . The tension spring  36  is thereby secured on the shaft  37  on the base plate  30  center-symmetrically relative to the sheave  35 . 
     FIG. 4 shows the drive unit  25  in a condition in which it lies against the photoconductor drum  2 . A roller arrangement  20  presses against the drive drum  40  with predetermined spring force. As a result thereof, the paper web  6  which is transported through between the drums  40  and  20  is moved by the drive drum  40  on the basis of a friction lock. The drive drum  40  is in turn connected to the stepping motor  41  via a toothed belt drive. The entire drive unit  25  is flanged to a printer housing via a bearing block  44 . A common bearing axis  42  is seated at the bearing block  44  by the ball bearing  43 , the common bearing axis accepting both the rotational motion of the drive drum  40  and enabling a swivel motion of the drive elements around the swivelling axis B. In order to enable the swivel motion, the drive components such as motor  41 , deflection rollers  58  and swivel jaws  56  are mounted on a carrier plate  47  that is connected to the bearing block  44  via a gas compression spring  49  as well as via the bearing axis  42 . 
     Threads  45  located in the bearing block  44  serve for the acceptance of fastening screws with which the bearing block  44  is secured to the printer housing  18 . The entire drive unit is adjustable within the printer housing  18  via guide surfaces  46 . The carrier plate  47  is in turn adjustable relative to the bearing block  44 , whereby a first adjustment screw  51  and a second adjustment screw  52  against which cylinder pins at the carrier side strike are provided in the bearing block  44 . 
     The gas compression spring  49  is connected to the carrier  47  by the screw connection  50  and is connected to the bearing block  44  by the screw connection  48 . The carrier  47  and the bearing block  44  can be locked relative to one another with the locking means  54 . 
     A paper web  6  that is introduced into the drive unit  25  between the drive drum  40  and the counter-pressure drum  20  is guided to a paper sensor  55  by a guide plate  53 . The paper sensor  55  senses the paper  6  over the entire width of the printable region of the photoconductor drum  2 . As a result thereof, both the lateral paper edges as well as potential margin perforations of the paper web  6  can be recognized. In the region of the transfer printing zone  5  of the printer unit, the paper  6  is pressed against the surface  19  of the photoconductor drum  2  by the spring-seated swivel jaws  56 . A known corotron means  57  generates a high-voltage with which the toner located on the photoconductor drum  2  is drawn to the paper  6 . The deflection rollers  58  forward the paper  6  to a mark sensor  59  that recognizes any printing or cutting marks that may be present on the paper web  6 . Grounded electrical connections  61  (anti-static plates) carry off any residual electrical charges located on the paper  5 . 
     When margin perforated paper  6  is transported with the paper transport, the margin perforations can be sensed with a pin feed wheel  60 . 
     FIG. 5 shows a three-dimensional illustration of the paper drive  25 . In particular, the cylinder pin  66  mounted at the carrier plate  47  that interacts with the adjustment screw  52  screwed in the bearing block  44  as well as the screw connection of the gas compression spring  49  can be seen therefrom. 
     The paper  6  is guided by a guide surface  69  above the deflection drums  58 . The sensing of the paper  6  with the mark sensor  59  also ensues in this region. Further, a seating rule  65  is provided in this region, this being employed for the printer start. Newly inserted paper  6  that comprises margin perforations thereby has a page start placed against a marking of the rule  65  that corresponds to the page length, the margin perforation is brought into engagement with the pin wire  60 , and the printing operation is initiated. 
     In the transfer printing area, a drive motor  68  pulls a corotron wire from the corotron wire cassette  57  according to the page width to be printed. The mark sensor  59  is displaceable in the direction E along the rod  73 . The plate  64  covers the drive motor  41  and serves, in particular, as electromagnetic shielding. Corresponding to the front bearing block  44 , a back bearing block  67  is also provided, this being likewise secured to the printer housing. 
     The lock mechanism  54  merely has to be unlocked in order to move the drive unit  25  from the operating position (FIG. 4) into the service position (FIG.  6 ). Due to the upwardly acting force of the gas compression spring  49 , the drive unit  25  then automatically pivots up. The operator need exert practically no force. The carrier plate  47  together with all parts mounted at it thereby pivots around the drive or swivelling axis  42  relative to the bearing block  44  or, respectively, relative to the printer housing. The counter-pressure roller  20  thereby also pivots along, so that the paper  6  clamped between drive roller  40  and counter-pressure roller  20  executes no relative motion. The stepping motor  41  remains under power during the pivot event, so that it exerts a retaining moment on the drive roller  40 . Due to the common bearing of the drive roller  40  and the carrier plate  47  in the shaft  42 , no relative motion derives between the drive roller  40  and the other components mounted at the carrier  47 , such as the swivel jaws  56  and the deflection rollers  58 . As a result thereof, the clamped paper remains lying attitudinally exact at the drive unit  25 . A potential paper compensation required with respect to following units of the printer ensues with the loop-drawing means  26 . The loop drawing means  15  can effect a paper compensation relative to the pre-centering means  8 . The loop-drawing means  26  is pivoted up in the example of FIG. 6, so that it accepts a length of paper becoming free when the unit  25  pivots up and forms a loop relative to the paper position (shown with broken lines) of the working position. 
     When, after the service work has been carried out, the drive unit  25  is in turn pivoted back into the working position, then the loop-drawing means  26  gives the stored length of paper back, so that the paper  6  subsequently comes to lie again in exactly the same position with respect to the other printer units, particularly with respect to the photoconductor drum  2 , as in the working position before being swivelled up. As a result thereof, it is possible to resume an uninterrupted printing event with exact attitude. 
     FIG. 7 shows a specific embodiment of the invention wherein a paper web  6 , after the printing of the side, is supplied to a turnover station  71  via a deflection roller  70 . The paper that has been turned over is thereby re-supplied to the pre-centering means  8  at a station  72 . The paper web  81  that has been turned over thereby lies page-offset relative to the paper web  6 . Both webs pass through the transfer printing station  5  simultaneously. As a result thereof, both the front side of the paper web  6 —in the first pass—as well as its back side are printed due to the turned-over sub-sections  81 . The duplex-printed paper  81  is then supplied to further units. Optionally, the web section  6  can already be fixed before the turned-over section is resupplied to the printing station  81 . The displacement arrangement with the two detent plates  9  and  9   a  shown in FIG. 3 serves, in particular, for guiding the two web sections lying side-by-side. 
     The turned-over paper web  81  is coupled into the pre-centering means  8  at the location  72 . 
     FIG. 8 again shows a sectional view of various components of the paper drive  25 , particularly the connection of the carrier plate  47  to the bearing block  44  via the gas compression spring  49  as well as its bearing  48  and  50 . 
     FIG. 9 shows the frame of the carrier  47 . It is particularly implemented as a cast member. In the illustrated embodiment, a receptacle is provided for a corotron cassette  57 . In one embodiment that conducts two parallel paper webs  6  and  6   a  past the transfer printing station, a second receptacle would be provided for the second paper web  6   a . The first paper web  6  would thereby be transported in the region  77 , the second paper web  6   a  in the region  78  of the paper channel  74 . The paper width sensor  21  is also shown in FIG.  9 . It contains light-emitting diodes and allocated light sensors that sense the paper web  6  or, respectively, both paper webs  6  and  6   a  over the full width. The paper webs  6  and  6   a  are thereby conducted through a gap  75  of the paper width sensor. A guide plate  76  also serves for paper guidance. In one operating mode for processing margin perforated paper  6 , the pin feed wheel sensor  85  is additionally utilized, this engaging into the margin perforations of the paper  6 ,  6   a  and being capable of exactly measuring the position and speed of the paper web  6 ,  6   a.    
     FIG. 10 shows the pin feed wheel in a pivoted-in position, whereby the pins project beyond the paper guidance plane  67 . The margin perforations of the paper engage into the pins. This pin feed wheel  60  can be pivoted in or, respectively, out along direction F with an actuation lever  86 . 
     FIG. 11 shows the pivoted-out position, wherein the pins  82  do not project beyond the surface  67 , as well as further details of the pin feed wheel sensor  85 . The pin feed wheel  60  is seated on a shaft  87  that likewise carries a gearwheel  88 . A magneto-resistive sensor  91  detects pulses of the metal cogs of the gearwheel  88 . A second magneto-resistive sensor  92  detects whether the pin feed wheel sensor  85  is in the pivoted-in or pivoted-out position. To this end, it interacts with the magnet  93  that is mounted on the guide surface  67 . The sensor assembly is electrically connected to a device controller. The overall pin feed wheel sensor  85  can be locked in the pivoted-out or, respectively, pivoted-in position with a catch mechanism  90 . 
     FIG. 12 shows the drive shaft  40  and the carrier or bearing shaft  42  of FIGS. 4 through 8 as section along the conveying direction. It can be seen that the carrier shaft proceeds along the axis  94  coaxially with the drive shaft  40 . The carrier shaft  42  is respectively seated with a ball bearing  95  in the front and back bearing blocks  44  or, respectively,  67 . It lies in the carrier  47  with a clearance fit. The drive shaft  40  is seated on the carrier shaft  42  with ball bearings. 
     Although other modifications and changes may be suggested by those skilled in the art, it is the intention of the inventors to embody within the patent warranted hereon all changes and modifications as reasonably and properly come within the scope of their contribution to the art.