EP1655253B1 - Sheet handling mechanism with sheet position detection - Google Patents

Description

The invention relates to a sheet processing device with position detection of a sheet.

BACKGROUND OF THE INVENTION

Sheet processing devices are known, for example of the scanner, printer or copier type, which comprise a leaf circulation path and a sheet detection member in the circulation path.

In general, the detection member comprises a first sensor detecting the arrival of a leading edge of the sheet and causing a change of scroll speed of the sheet for processing.

The time required to change the scrolling speed and the resulting play adjustments in the driveline make it unclear when the speed of the sheet is again stabilized, which hampers the use of this first detection as a signal. synchronization for subsequent processing of the sheet.

A second sensor is thus used, located downstream of the first sensor sufficiently far from it so that when the leading edge of the sheet arrives opposite the second sensor, its speed is stabilized. The second sensor is then able to provide a reliable timing signal for the start of sheet processing, such as the analysis or printing of the sheet. The second sensor is also able to provide a reliable synchronization signal for the end of sheet processing by detecting the trailing edge of the sheet.

Document is known US 2004/061283 a device according to the preamble of claim 1. However, the cooperation of the probes with the sensor only gives rise to two changes in the state of the signal of the sensor during the displacement of the sheet.

OBJECT OF THE INVENTION

The invention relates to a sheet processing device comprising a simplified device for detecting the position of the sheets.

With a view to achieving this object, a sheet processing device according to claim 1 is provided.

• une première transition du premier état au second état lorsque le palpeur poussé par le bord d'attaque de la feuille passe de la position de repos à la position intermédiaire ;
• une deuxième transition du second état au premier état lorsque le palpeur toujours poussé par le bord d'attaque de la feuille passe de la position intermédiaire à la position escamotée dans laquelle le palpeur est maintenu par la feuille;
• une troisième transition du premier état au second lorsque le palpeur passe sous l'action de l'organe de rappel de la position escamotée à la position intermédiaire lorsque le bord de fuite de la feuille quitte le palpeur ;
• et, selon une succession rapide, une quatrième transition du second état au premier état lorsque le palpeur passe de la position intermédiaire à la position de repos toujours sous l'action de l'organe de rappel.

Thus, during the passage of the sheet in the circulation path at the probe, the sensor changes state several times:

• a first transition from the first state to the second state when the probe pushed by the leading edge of the sheet moves from the rest position to the intermediate position;
• a second transition from the second state to the first state when the probe always pushed by the leading edge of the sheet passes from the intermediate position to the retracted position in which the probe is held by the sheet;
• a third transition from the first state to the second when the probe passes under the action of the return member from the retracted position to the intermediate position when the trailing edge of the sheet leaves the probe;
• and, in rapid succession, a fourth transition from the second state to the first state when the probe passes from the intermediate position to the rest position always under the action of the return member.

According to the invention, these transitions are used to control the speed change of the sheet and / or to serve for synchronizing the beginning and the end of the treatment of the sheet.

Thus, it is possible to perform with a single sensor a number of actions that previously required two separate sensors. The processing device is thereby simplified.

BRIEF DESCRIPTION OF THE DRAWINGS

• les figures 1 à 3 sont des vues en coupe schématiques partielles d'un scanner selon l'invention illustrant le chemin de circulation des feuilles dans le scanner, sur lesquelles le parcours d'une feuille est figurée à des instants successifs ;
• la figure 4 est une vue en perspective du palpeur et du capteur associé ;
• la figure 5 est un graphe figurant, en fonction du temps, la durée d'analyse d'une feuille, l'état du capteur, et la vitesse de la feuille.

The invention will be better understood in the light of the description which follows with reference to the figures of the appended drawings in which:

• the Figures 1 to 3 are partial schematic sectional views of a scanner according to the invention illustrating the path of circulation of the sheets in the scanner, on which the path of a sheet is shown at successive times;
• the figure 4 is a perspective view of the probe and the associated sensor;
• the figure 5 is a graph showing, as a function of time, the duration of analysis of a sheet, the state of the sensor, and the speed of the sheet.

DETAILED DESCRIPTION OF THE INVENTION

With reference to figures 1 and 4 , the treatment device of the invention, here a scanner, comprises a circulation path 1 of leaves F. Here is shown a sheet F engaged in the circulation path 1. In a manner known per se, the sheet is moved in the circulation path 1 by drive rollers not shown.

The circulation path 1 passes a scanning member 2 and ends with an ejection channel 4. In the illustrated embodiment, the circulation path 1 defines in known manner a loop 5 which makes it possible to restart the sheet F towards the scanning member 2 to scan the other side of the sheet F.

A detection device 10 is mounted upstream of the scanning member 2.

The detection device comprises a probe generally designated 16.

The probe 16 comprises an arm 11 fixed in rotation on an axis 12 carried by bearings not shown. The probe further comprises a pallet 13 also fixed in rotation on the axis 12. The rigid arm 11 - pallet 13 is biased by a return spring 15 to a rest position in which the arm 11 extends across of the circulation path 1 upstream of the scanning member 2. The probe 16 is associated with a sensor 14 with two states, here an optical sensor whose state is a function of the presence or absence of the pallet 13. 14. The pallet thus forms an interaction element of the probe with the sensor. The return force of the spring 15 is calculated so that the probe can pivot under the action of the sheet F flowing in the circulation path 1 between the rest position illustrated in FIG. figure 1 and a retracted position visible to the figure 3 .

During the rotation of the probe 16, the pallet passes next to the optical sensor 14 which delivers a signal in a first state when the pallet 13 is offset relative to the optical sensor 14, and a second state when the pallet 13 is opposite the optical sensor 14.

These two states are represented on the graph of the figure 5 by level n1 for the first state and level n2 for the second state.

When the probe is in the rest position, the pallet 13 is offset relative to the optical sensor 14 so that the signal of the optical sensor 14 is in the first state of level n1.

To the figure 1 , the sheet F is shown, while it moves at a high speed of travel, at the precise moment when its leading edge F1 approaches the probe 11.

The leading edge F1 pushes the probe 11 towards an intermediate position visible to the figure 2 between the rest position and the retracted position, in which the pallet 13 is in front of the optical sensor 14. The signal of the optical sensor 14 then passes to the second state of level n2. This first transition is noted t1 on the graph of the figure 4 .

According to the invention, this transition is used to control the slowing of the sheet F. For this purpose, the control module 50 of the scanner is configured to, in response to the detection of the transition t1, send to the drive rollers a slowing order to change the speed of the sheet F from a high scrolling speed to a slower analysis speed.

During this transition, the leading edge F1 continues to push the arm 11 so that the probe reaches the retracted position illustrated in FIG. figure 3 . In this position, the pallet 13 is passed on the other side of the optical sensor 14, so that the pallet 13 is again shifted relative to the optical sensor 14.

The signal from the optical sensor 14 transits back to the first state of level n1. This second transition is noted t2 on graph 4.

According to the invention, the second transition t2 is used as a synchronization signal for the beginning of the analysis of the sheet F by the scanning member 2.

For this purpose, the shape of the arm 11 cooperating with the leading edge F1 and the width of the pallet 13 are studied so as to leave a sufficient time between the first transition t1 and the second transition t2 so that at the moment when the second transition t2 intervenes, the speed of the sheet F is stabilized at the analysis speed.

We see on the graph of the figure 4 in thick mixed lines the evolution of the speed of the sheet F between the scrolling speed V1 and the analysis speed V2. It can be seen that the speed of the sheet F is stabilized at the analysis speed V2 well before the transition t2.

Knowing the distance between the scanning member and the position of the leading edge F1 of the sheet when it pushes the arm 11, it is then easy to determine the duration ΔT or the number of steps of the drive motors required so that the leading edge F1 reaches the scanning member 2.

The control module 50 is configured to activate the scanning device after a corresponding count counted from the detection of the transition t2.

On the graph of the figure 4 is shown in thick lines analysis by the scanning member 2, the beginning begins after the duration ΔT with respect to the transition t2.

During the analysis, the sheet F keeps the probe in the retracted position. The duration of the analysis depends on the length of the sheet F. We see on the graph of the figure 4 that the state of the optical sensor 14 remains at level n1 during the analysis.

Then, a little before the end of the analysis, the trailing edge F2 reaches the curved end of the probe 11 and then exceeds it.

The probe 11 is then released and returned by the return member to the rest position, passing through the intermediate position.

This return movement gives rise to a third transition t3 of the signal of the optical sensor 14 when the probe 11 moves from the retracted position to the intermediate position, and, in rapid succession, to a fourth transition t4 of the signal of the optical sensor 14 when the probe 11 passes from the intermediate position to the rest position.

According to the invention, the transition t3 is used as a synchronization signal for the end of the analysis of the sheet F by the scanning member 2.

For this purpose, the control module 50 is configured to deactivate the scanning member 2 after a time delay ΔT from the detection of the transition t3.

On the graph of the figure 4 , we distinguish the end of the offset analysis of the duration ΔT with respect to the transition t3.

Thus, with a single sensor, it is possible to control the speed change of the sheet and to synchronize the beginning and the end of the analysis.

The invention is not limited to what has just been described, but on the contrary encompasses any variant within the scope defined by the claims.

In particular, although it has been indicated that the scanning device is activated after a time ΔT counted from the transition t2, it will be possible to implement other types of synchronization, such as for example generating a top storing the scanned data while the scanning device has already been activated. Similarly, the transition t3 can be used to generate a top stop storing the scanned data while the scanner remains active.

Although it has been indicated that the start and end times are the same, these times may be different, for example to take into account a shape of the arm 11 which induces different movement times of the probe as it cooperates with the leading edge or the trailing edge of the sheet. In addition, these times may be variable depending on various parameters such as the speed of analysis.

Although it has been indicated that the sensor and the element of interaction with the sensor carried by the probe are here an optical sensor and a pallet, it will more generally be possible to use any sensor that cooperates with an interaction element of the probe to be in a first state when the probe is in the rest position or in the retracted position and in a second state when the probe is in an intermediate position between the rest position and the retracted position. For example, a hall effect sensor interacting with a metal interaction element carried by the probe may be used.

Preferably, a non-contact sensor will be used to avoid any friction causing wear that may in the long run generate shifts in the synchronizations.

Although it has been indicated that the probe is pivoting, it will be more generally possible to implement the invention with a probe movable between a rest position and a retracted position, such as for example a sliding probe. The probe can then be made in the form of a plate having a window, this window coming opposite the sensor in the intermediate position of the probe. The interaction element is then the window.

The invention does not apply only to scanners, but to any type of sheet processing device, such as for example printers, copiers and applies not only to a front-and-back processing device as illustrated, but also to single-sided devices.

Claims (6)

1. A sheet processor device comprising a sheet travel path (1) and a detector device (10) for detecting sheets in the travel path (1), the detector device including a feeler (16) urged towards a rest position by a return member and being movable between the rest position in which it extends across the travel path (1) and a retracted position towards which it is pushed by a leading edge (F1) of a sheet passing along the travel path, and a two-state sensor (14) that co-operates with the feeler (11), the sensor and the feeler co-operating in such a manner that the sensor is in a first state when the feeler is in the rest position or in the retracted position, the device being characterized in that the sensor is in a second state when the feeler is in an intermediate position between the rest position and the retracted position.
2. A device according to claim 1, characterized in that the detector device comprises a contactless sensor (14), and in that the feeler (16) includes an interaction element (13) for interacting with the sensor (14).
3. A device according to claim 1, characterized in that the feeler (16) is pivotally mounted.
4. A device according to claim 1, characterized in that it includes a control module (50) configured to detect a transition (t1) of the sensor (14) from the first state to the second state when the feeler (16) passes from the rest position to the intermediate position, and to change the speed of the sheet (F) along the travel path in response to detecting this transition (t1).
5. A device according to clam 4, characterized in that it includes a control module (50) configured to detect a transition (t2) of the sensor from the second state to the first state when the feeler (16) passes from the intermediate position to the retracted position, and to use this transition (t2) as a synchronization signal for the beginning of processing of the sheet (F).
6. A device according to claim 1, characterized in that it includes a control module (50) configured to detect a transition (t3) of the sensor (14) from the first state to the second state when the feeler (16) passes from the retracted position to the intermediate position, and to exploit this transition (t3) as a synchronization signal for the end of processing the sheet (F).

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