EP0937281A1

EP0937281A1 - Method and device to control ejection of sheets from input compartments in a paper output device belonging to a printing and photocopying system

Info

Publication number: EP0937281A1
Application number: EP97945771A
Authority: EP
Inventors: Stephan Pilsl; Bernward Heller; Gerhard Oberhoffner
Original assignee: Oce Printing Systems GmbH and Co KG
Current assignee: Canon Production Printing Germany GmbH and Co KG
Priority date: 1996-10-22
Filing date: 1997-10-21
Publication date: 1999-08-25
Anticipated expiration: 2017-10-21
Also published as: CA2269488A1; CA2269488C; DE59710097D1; JP4091986B2; JP2001502649A; WO1998018051A1; EP0937281B1; US6179281B1; DE19781178D2

Abstract

In order to control the ejection of sheets from input compartments in a paper output device belonging to a printing and photocopying system, verification occurs as to whether a previously processed sheet has been removed as soon as it is has been established that at least one input compartment is almost empty. Ejection of the sheet immediately following according to the order of processing occurs thereafter. These steps are repeated until the input compartment is empty. Printing operation is then stopped.

Description

description

Method and device for controlling the delivery of sheets from input compartments of a paper delivery device of a printing and copying device

The invention relates to a method and a device for controlling the delivery of sheets from input compartments of a paper delivery device of a printing and copying device.

In the case of high-performance printing and copying devices, in particular, a plurality of input pockets are usually provided in a paper delivery device, in which sheets to be printed or other printed matter are inserted; In the following, we will only speak of "leafing" in this context. Sheets are withdrawn from the input compartments and conveyed to processing devices of the printing and copying devices by means of transport devices.

Several input trays are provided not only to increase the capacity of a printing and copying device, in that sheets can be pulled from different input trays in succession as soon as the previous compartment is empty, but also so that different print material, for example differently colored ones, is available in the individual input trays Sheets, sheets with differently colored forms, sheets of different formats, such as forms etc. can be accommodated. For example, white sheets could be provided in one compartment, sheets provided with a company logo in another compartment, personalized or colored sheets in a third compartment, etc.

With the help of a correspondingly designed control, printing or copying obs can thus be carried out, in which different sheets are accessed by controlling different input tachers in a very specific sequence. If a plurality of input trays are provided in a paper delivery device, the transport routes from the individual input trays of the paper delivery device, for example, to a sheet transfer point at which the sheets are delivered to the downstream printing and copying device are of different lengths. If the sheets are subtracted from the individual compartments in the same order in which they are processed, there can be relatively large gaps, ie gaps, between the individual sheets due to the often very different transport routes.

In order to avoid such large gaps between individual sheets during the transport to the sheet transfer point or to the printing and copying device, the differently long transport routes and the resulting differently long duration of a sheet transport can be taken into account by the individual specialists to the sheet transfer point.

For example, a sheet from an input tray from which a long transport path has to be traveled to the sheet transfer point can be pulled off earlier than a sheet from an input tray from which a relatively short transport path has to be covered, although the sheet which was later removed before the earlier one peeled sheet is processed.

The order in which the individual sheets are withdrawn from the input trays, which is referred to below as the sheet withdrawal order, can thus differ from the order in which the sheets are processed, which is referred to below as the sheet processing order. By means of an appropriately designed control system, however, the distance between the individual sheets can be minimized or the occurrence of large gaps can be avoided, and the performance of high-performance printing and copying devices can thus be increased still further. Nevertheless, even with an optimally designed control system, problems can arise if a compartment is empty and this is determined too late. For example, if a sheet to be processed later in the processing order, which has to go through a relatively long transport path, is withdrawn from an input tray earlier than a sheet which is to be processed beforehand in the processing order and which has to go through a relatively short transport path, the problem can arise that the Sheet that is later pulled out of the corresponding compartment, however earlier in the processing sequence, cannot be removed because the corresponding input compartment is empty. In such a case, the sheet processing order can no longer be adhered to.

The above problem is illustrated below using a simple example (see FIG. 1). To carry out a print job, sheets from a compartment B and from a compartment D are required, which are to be processed in the order B1-B-D1. B _{λ denotes} a first sheet from compartment B, B- a second sheet from compartment B and D _λ a sheet from compartment D.

Tray D should be considerably further away from the sheet transfer point than tray B. To optimize the printing and copying time, a deduction sequence D ₁ -B ₁ -B ₂ is therefore expedient. It is also assumed that there is only one sheet left in compartment B.

The device control is then designed, for example, so that the sheet D _{x is} withdrawn from the tray D at the same time as the sheet Bi from the tray B. Due to the requirement that only one sheet is present in the tray B, this is now Tray B empty. Thus, the second sheet B ₂ can no longer be removed from the tray B and therefore the processing sequence B ₁ -B ₂ -D ₁ can no longer be observed. 2 shows a diagram of a device control which ensures that the processing sequence Bi- B ₂ -Dι _. is observed. For this purpose, the sheet delivery times or points in time are shown on the ordinate in FIG. 2 and the path that a sheet has to travel from the respective compartment to the sheet transfer point 10 (m FIG. 1) is plotted on the abscissa.

As can be seen from the diagram in FIG. 2, the sheet B _{x is} drawn off from the input compartment B in relation to the zero point of the diagram after a time of 1.5 s and transported along a transport path b indicated by an arrow. Here are mt VB _! and HB denotes the front or rear edge of the sheet B _λ . At the time 2.3s, the sheet B _JL has reached the sheet transfer point 10 (FIG. 1), where, as is indicated on the abscissa of the diagram in FIG. 2, the transport path b (0 mm) ends.

In order to keep the distances between the sheets to be printed in the processing sequence B-B ₂ -D as small as possible, the sheet D is withdrawn from the input tray D at the same time at which the sheet Bi has been removed from the tray B.

Due to the requirement that only one sheet is present in the input tray B, a sensor S assigned to the tray B reports after the sheet B has been removed that the input tray B is now empty. (For this reason, the leading and trailing edges VB ₂ and HB ₂ of sheet B ₂ m in FIG. ₂ are only shown in dashed lines.) This is determined at a point in time which corresponds to about 1.9 s on the ordinate.

At this time, however, the sheet Di pulled from the input tray D is located, for example, at the point P on a transport path d indicated by an arrow. Since the tray B is empty and therefore a second sheet B2 cannot be pulled off, the processing sequence Bi-B _^ -D cannot be maintained and the printing and copying device is or must be stopped.

After the printing and copying device has been stopped, at least the sheets of a print job that have already been removed from the respective exhaust tachers must be removed from the printing and copying device by the operating personnel. In the example case described above, this is sheet D. In addition, control problems can occur in the subsequent printing and copying operation in that the controller is not aware of which and how many sheets have been removed from the printing and copying device by the operating personnel.

The object of the invention is therefore to provide a simple method for controlling the delivery of sheets from input compartments of a paper delivery device of a printing and copying device, with which it is ensured that the insertion of sheets is user-friendly. Furthermore, a facility is to be created to carry out the method.

According to the invention, this object is achieved in a method for controlling the delivery of sheets from input compartments of a paper delivery device of a printing and copying device and with a device for performing the method by the features of claims 1 and 6, respectively. Advantageous further developments are the subject of further claims.

In the method according to the invention for controlling the delivery of sheets from input trays of a sheet delivery device of an electrophotographic printing and copying device, all the input tiers are constantly monitored to determine whether an emgao tray is nearly empty. Once it has been determined that at least one of the input compartments is approximate is empty, the printing or copying operation is stopped or the device control checks whether a sheet preceding the specified processing order has already been removed or is still available in the corresponding input compartment.

Subsequently, a sheet that follows the processing order is subtracted from an input tray. The above steps are repeated until an input bin is empty. However, this can be prevented by refilling the relevant sheets in good time for the compartment that is reported to be almost empty. If this is overlooked or cannot be done for some reason, once an input tray is actually empty, the electrophotographic printing and copying operation is stopped.

According to the invention, the constant checking of the input compartments as to whether one of them is nearly empty has the particular advantage that the operator only receives the corresponding printed material again as soon as this is indicated, or at the latest when the printing and copying operation has been stopped has to bring in an almost empty or empty compartment. Since, when using the method according to the invention, the processing sequence is not yet disturbed at this point in time, since no specified single sheet is missing in the sequence, as in the control method described at the outset, the sheets belonging to a print job and already removed from the input compartments do not need to be removed from the paper delivery device or possibly even from the printing and copying device.

According to an advantageous development of the method according to the invention, a number of previous sheets can also be checked to determine whether the sheets preceding the given processing sequence have already been deducted or still exist in the corresponding input compartments.

In a somewhat simplified implementation of the method according to the invention, as soon as it has been determined that at least one of the dispensing compartments is approximately empty, the deduction order can also be matched to the full condition or individual dispensing compartments. For example, the control of the individual compartments is then changed so that the deduction order with respect to the sheets to be withdrawn from the individual input compartments is brought into close or complete agreement with the processing order. The result of this is that the distances between individual sheets become larger, but the processing order is reliably maintained. A certain advantage can also be seen in the fact that the input tray, which is shown as being approximately empty, can be completely emptied without the processing order being impaired thereby.

Under special conditions of use, however, it may also be expedient to stop the electrophotographic printing and copying operation as soon as it has been determined that at least one of the receiving compartments is approximately empty. However, this measure was probably only allowed to be used in relatively rare cases.

To carry out the method according to the invention, a sensor is assigned to each input compartment, which emits the signal, one compartment is almost empty, as soon as only about twenty sheets or fewer are left in the input compartment. According to the invention, the sensor is connected to a control unit which changes or increases the time intervals between the sheets, which are subtracted from the individual input trays, when a signal that a compartment is nearly empty is present, which ultimately complies with the processing order. Each input compartment is preferably also assigned a second sensor, for example in the form of a light barrier, which then emits a signal as soon as the input compartment is completely empty.

The invention is explained in more detail below with reference to the accompanying drawings. Show it:

Fig.l a paper delivery device with a plurality of input compartments of a printing and copying device;

2 shows a possible control diagram for controlling the delivery of sheets from input compartments of a paper delivery device of a printing and copying device, and

3 shows a control diagram for controlling the delivery of sheets from input compartments of the paper delivery device, in which the method according to the invention is implemented

In Fig.l, a paper delivery device has a plurality of input compartments A to D and an external feeder E. Sheet stacks la to ld are accommodated in the input compartments A to D. The sheet stacks la to ld are printed upwards against sheet removal devices 4a to 4d by lifting devices 2a to 2d. Furthermore, sensors 5a to 5d are arranged on the input compartments A to D, which emit a signal as soon as the corresponding compartment of the compartments A to D is almost empty. Furthermore, a sensor S is arranged on the bottom of the compartments A to D, which emits a signal when the respective compartment is empty.

By means of transport devices 6a to 6d and 7a to 7d, sheets which have been drawn off from the respective input compartments A to D by means of the sheet pull-off devices 4a to 4d assigned to these compartments are transported on transport routes a to d and are finally taken over by a further transport device 8 , from which the leaf ter are transported to a sheet transfer point 10, at which the sheets are transferred from the paper delivery device to a printing and copying device, not shown.

Sheets introduced at the external feeder E are transported along a transport path e by means of transport devices 7e until they are taken over by the transport device 7d, which is provided at the end of the transport path d. For transport monitoring, light barriers 9 are provided at different points in the transport routes a to e.

In the case of automatic sheet delivery, for example, a sheet which has been drawn off from a sheet stack la accommodated in the compartment A by means of the sheet removal device 4a is transported along the transport path a to the sheet transfer point 10 by means of the transport devices 6a, 7a and 8. Analogously to this, sheets drawn off from the input compartments B, C and D are moved along the transport paths b to d by means of the transport devices 6b, 7b, 8 and 6c, 7c, 7b, 8 and 6d, 7d, 7c, 7b and 8 to the sheet transfer point 10 transported.

As can be seen from FIG. 1, the transport path b is the shortest and the transport path d is the longest of the transport paths a to d from the input compartments A to D to the sheet transfer point 10.

FIG. 3 shows a diagram of a control system which works according to the method according to the invention. In FIG. 3, different times in seconds (s) are again plotted on the ordinate and the length of transport routes in mm is plotted on the abscissa. A sheet processing sequence Bx-B ^ Dx should also be observed in the diagram shown in FIG. In contrast to the possible control described with reference to FIG. 2, however, a sensor, for example sensor 5b, should have indicated that input compartment B is almost empty. As soon as the determination has been made that an input box is almost empty, the method according to the invention comes into play.

This means that in the present case the sheet B _{} is} again subtracted, for example at the time 1.5 s. Sensor S assigned to compartment B determines at about 1.9 s that compartment B is not yet empty after sheet B has been pulled off, or at least one sheet is still present.

Immediately afterwards, approximately at the time 2.1s, the sheet pull-off device 4d of the tray D is activated. The sheet D is pulled off and requested on the transport path d indicated by an arrow in the direction of the sheet transfer point 10. At about the time 2, 3s, the sheet B is then also pulled off by means of the sheet pull-off device 4b and is conveyed on the transport path b indicated by an arrow in the direction of the sheet transfer point 10.

Thus, since sheet D _{x was} withdrawn from tray D with respect to sheet B _{2 with a} delay and transferred to the transport devices 6d, the second sheet B- was withdrawn from tray B without delay, however, between sheet B and the sheet D _{x created} a larger space.

If, after the sheet B _± had been removed from the sensor S, it was reported that the tray B is now empty, no sheet in the tray D would have been removed from the paper stack 1d accommodated there.

As can be seen from the diagram in FIG. 3, the processing sequence B ₁ -B ₂ -D ₁ m of the printing and

Copier direction guaranteed. Only the space or the gap between sheet B ₂ and sheet D is _λ due to the response of the sensor 5b associated with the compartment B, which has indicated that the compartment B is almost empty, until the compartment B is actually empty in the example described.

Reference list

10 sheet transfer point la to ld sheet stack

2a to 2d lifting device

4a to 4d sheet take-off device

5a to 5d sensor (almost empty)

6a to 6d transport device

7a to 7d transport device 7 7ee transport device

8 transport device

9 light barrier a to d transport route

E external feed ee transport route

S sensor (empty)

Claims

claims

1. Method for controlling the delivery of sheets from input compartments of a sheet delivery device of a printing or copying device,

where one is different from a sheet processing order,

it is reported whether at least one of the input compartments is almost empty,

and in which the printing or copying operation is stopped as soon as an almost empty input compartment is reported.

2. Method for controlling the delivery of sheets from input compartments of a sheet delivery device of a printing or copying device,

in which a sheet withdrawal order differs from a sheet processing order only until it has been determined that at least one of the input compartments is approximately empty,

and in which the sheet withdrawal order is selected in accordance with the sheet processing order as soon as at least one of the input compartments is approximately empty.

3. The method according to claim 2, characterized - characterized in that with at least one approximately empty input tray that next sheet is only deducted according to the sheet processing sequence if a sheet to be processed according to the sheet processing sequence is already subtracted before or the next sheet corresponding input compartment is available, and that printing or copying is stopped if an input tray is empty.

Method according to claim 3, so that the sheet processing before the next sheet is in the processing sequence immediately before the next sheet.

Method according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that a signal that a bin is almost empty is generated as soon as there are about twenty sheets in an input bin.

Device for performing the method according to one of the preceding claims, characterized in that each input compartment (A to D) is assigned a sensor (5a to 5d) which emits a signal as soon as the input compartment to which it is assigned is almost empty .

Device according to Claim 6, characterized in that the sensors (5a to 5d) are connected to a control unit which, when a signal generated by an activated sensor (5a to 5d) is present, subtracts the time intervals between the individual input compartments (A to D) Scroll changes.

Device according to claim 6 or 7, characterized in that a second sensor (S), preferably a light barrier, is arranged in each input compartment (A to D), which generates a signal as soon as the input compartment (A to D) assigned to it is empty.