NL2026907B1

NL2026907B1 - Printer with a Plurality of Holders for Storing Print Media

Info

Publication number: NL2026907B1
Application number: NL2026907A
Authority: NL
Inventors: M Gerrits Antonius
Original assignee: Canon Production Printing Holding Bv
Priority date: 2020-11-17
Filing date: 2020-11-17
Publication date: 2022-07-01
Also published as: DE102021128829A1

Abstract

printer comprising a number of holders (12) for storing print media (18), and a detection system (24) configured to detect access events where an operator accesses one of the holders (12), characterized in that each holder (12) is associated with a timer (28) capable of counting the time that has passed since the holder has last been accessed.

Description

Printer with a Plurality of Holders for Storing Print Media The invention relates to a printer comprising a number of holders for storing print media, and a detection system configured to detect access events where an operator accesses one of the holders.

In such a printer, the holders may be loaded with media of different types, so that the media type may rapidly be changed in accordance with specifications in the print jobs.

Of course, it is also possible to use the holders for storing media of the same type, which permits a longer period of unattended operation of the printer for many or large print jobs with the same media.

The detection system that detects events where an operator accesses one of the holders is commonly used for automatically either stopping the operation of the printer or switching to another holder when the operator opens a storage compartment of the printer in order to get access to a holder.

In certain printers, in particular ink jet printers operating with water-based ink, it is recommended, in order to assure a high print quality and a smooth operation of the printer, that the media are appropriately conditioned in terms of temperature and humidity before they are being processed in the printer.

US 10,007,872 B2 describes a printing system which has a climatized local media store with relatively large storage capacity for storing and conditioning the media before they are transferred to the holders of the printer.

The workflow is scheduled such that the media are entered into the media store timely enough to be properly conditioned at the time when they are needed for printing and are transferred to the holders in an input section of the printer.

Since the holders have a limited storage capacity, the dwell time of the media in these non-climatized holders is generally so short that the conditioned state of the media does not change significantly before the media are actually fed into the print process.

On the other hand, the limited storage capacity of the holders implies that the holders will have to be reloaded in relatively short intervals, so that an operator must attend to the printer relatively frequently.

It is an object of the invention to provide a printer that can be operated in a mode of operation in which a properly conditioned state of the media can be assured more reliably and/or with less frequent intervention of an operator.

In order to achieve this object, the printer according to the invention is characterized in that each holder is associated with a timer capable of counting the time that has passed since the holder has last been accessed.

According to an embodiment the detection system is configured to detect events where new media sheets are loaded into an empty holder. According to an embodiment the holders are arranged to hold stacks of media sheets and the detection system is configured to detect the height of the stacks in the holders. The most typical and frequent reason for an operator to access one of the media holders is that the stock of media in this holder is depleted, so that the holder must be reloaded with fresh media. In the printer according to the invention, the detection system is used for an additional purpose, namely for triggering a timer when an empty holder is reloaded. In this way, by watching the time counts of the timers, it is possible to monitor individually for each holder how long media have been kept in that holder. Consequently, it is more easy for the operator to check whether the dwell time of media in a holder has been or will become so long that it must be feared that the media are no longer in a properly conditioned state. More specific features and further developments of the invention are indicated in the dependent claims. In the simplest case, the time counts of the timers may just be displayed on a user interface, so that the operator can keep track of the dwell times and can take appropriate action when necessary. The invention further relates to methods of media management in a printer having the feature described above.

In one embodiment, the timers are used for automatically generating a warning message or signal when the dwell time of the media in one of the holders exceeds a certain threshold which is stored in the timer in the form of a preconfigured run time. According to a further development, the run time may be adjusted in accordance with the amount of media that is still present in the holder. In this way, it is possible to take into account that the conditioned state of the media will prevail for a longer time when the holder accommodates a large bulk of media that exhausts the storage capacity of the holder almost completely. In contrast, if the amount of media present in the holder is relatively small, the media will more easily come into contact with ambient air in the holder and the temperature and humidity of the media will change more rapidly. Another useful option is to use the time counts of the timers for determining, manually or automatically, an order in which a plurality of holders that accommodate media of the same type are used for supplying the media to the print engine. If the media are always fed from the holder for which the dwell time of the media in the holder has been longest, the dwell times can be prevented from becoming exceedingly long. Then, by loading a large number of holders of the printer with media of the same type, it is possible to prepare the printer for an extended period of unattended operation without running the risk that the storage duration of the media in some of the holders becomes too long.

Embodiment examples will now be described in detail in conjunction with the drawings, wherein: Fig. 1 is a simplified diagram of a media input section of a printer according to the invention; Fig. 2 is a flow diagram of a routine for media management in the printer; and Fig. 3 is a flow diagram of another example of a media management routine. Fig. 1 is a schematic view of a media input section 10 of a printer having five holders 12 for storing print media and feeding them into a media feed path 14 of the printer.

In this example, the printer is a cut sheet printer, and the holders 12 each have a tray 16 supporting a stack of sheets of media 18. The holders 12 are configured as drawers which may be pulled out by an operator who wants to get access to the tray accommodated therein, as has been shown for the third holder from above in Fig. 1.

Asis well known in the art, each tray 16 is supported on a lift mechanism 20 and is thereby adjustable in height such that a topmost sheet on the stack of media 18 is always held level with a branch of the feed line 14 that is arranged in a fixed height, so that the topmost sheet can be supplied into the feed line by means of a feed roller 22.

A conventional detection system may be provided for detecting when a drawer is opened and for stopping the operation of the printer in that event. In the printer shown here, however, the detection system is not only configured for detecting the open and closed state of each drawer but also comprises, for each holder 12, a sensor 24 that can detect the fill state of the holder. In the example shown, the sensor 24 is an optical distance sensor that detects the height of the tray 16 by emitting light onto the lowermost sheet of the stack through a window 26 of the tray. Thus, the sensor 24 cannot only detect the height of the stack by measuring the height of the tray but can also detect whether or not there is at least one sheet on the tray. If there is not at least one sheet on the tray, then the light of the sensor will not be reflected, as has been shown for the open third holder in Fig. 1.

When the last sheet of a stack has been fed into the feed line, this is detected by the sensor 24, and the lift mechanism 20 lowers the tray 16 into the lowermost position so that the operator can readily place a new stack of sheets onto the tray once the drawer has been opened.

As soon as the new stack has been loaded onto the tray, this is also detected by the sensor 24, and a corresponding signal is sent to a timer 28 in a media management module 30 that forms part of the control system of the printer. This signal triggers the timer 28 which will start to count the time that has elapsed since the time when the media were loaded into the holder. The media management module 30 has five timers 28 in this example, one for each of the holders 12, so that the times can be counted individually for each holder.

Optionally, the time counts of the five timers 28 may permanently be displayed on a user interface of the printer, so that the operator can readily check how long the media 18 have already been kept in the various holders. If the operator judges that a stack 18 has been kept in the printer 10 for such a long time that the sheets may not be in the 5 properly conditioned state anymore, i.e. have not the correct temperature or not the correct humidity content, she may decide that the sheets of this stack should no longer be used for printing, and she may remove the stack from the holder and may return this stack into a climatized media store where the sheets can be reconditioned.

Itis observed that, in principle, a tray 16 may be reloaded with media sheets already at a time when the stack on that tray was not consumed completely. In that case, the operator would conveniently place the new sheets on top of the stack that has remained on the tray 16, with the consequence that the number of old sheets with poor conditioning would remain in the bottom part of the stack in that holder. In that case, however, the sensor 24 will not detect that the tray has become empty nor that new sheets have been loaded. As a consequence, the corresponding timer 28 will keep running and will continue to count the time from the moment at which the older sheets in the lower part of the stack had been placed onto the tray.

Ofcourse, the operators should generally be instructed to avoid the situation described above by first removing the old sheets from the tray, then placing the stack of new sheets directly onto the tray and then place the old sheets back on top of the stack, so that the older sheets will always be consumed first. It will be observed that, in that case, the tray 16 does in fact become empty, at least for a short time, and the sensor 24 will detect this event and will trigger the timer 28 correctly.

Another possible way to take advantage of the timers 28 will now be described in conjunction with Fig. 2. In that embodiment, a certain run time can be set in each timer 28, so that, when the timer has been triggered, it will stop counting the time and send a signal as soon as the time count has reached to the pre-set run time.

Fig. 2 illustrates a routine that will be run in the media management module 30 independently for each timer 28. In step S1, the timer is initialized with a first run time which is appropriately selected to assure that the state of the media sheets will not deviate too much from the properly conditioned state. Optionally, this run time may be made dependent upon the temperature and the humidity in the input section of the printer and/or upon a relation of the amount of media present in the holder to the total storage volume of the holder. The latter relation is relevant because the climate in the holder 12 will change the condition of the media sheets faster when the number of sheets in the stack is small and the air volume enclosed in the storage space is large. Similarly, in the situation discussed above, where a tray is reloaded with media sheets already at a time when the stack on that tray was not consumed completely, an adjustment of the run time may be made in view of the fact that the sheets that were still on the tray have now been exposed to ambient air.

A temperature sensor 32 and a humidity sensor 34 may be provided in the input section, as has been shown in Fig. 1. Optionally, separate temperature and humidity sensors may be provided for each holder 12. The run-time tr that is pre-set in step S1 may for example be calculated as follows: tr = to * W_T*|T-Tc|/T +W_H* |H-Hc|/H) wherein T is the actual temperature in the input section 10, T_c is the target value for the temperature in the properly conditioned state, H is the actual humidity in the input section, H_c is the target humidity in the optimally conditioned state, and W_T and W_H are weight factors for the temperature and the humidity. In step S2, it is checked whether the sensor 24 has indicated a reload-event, i.e. an event in which the tray was temporarily empty and then new sheets have been loaded. If that is not the case (N), the step S2 is repeated in regular intervals. If a reload event has been detected (Y), the timer 28 is started in step SS. Since the climate in the holder 12 will change the condition of the media sheets faster when the number of sheets in the stack is small, the run time is adjusted when the height of the stack of media decreases. In step S4, it is checked whether the feed roller 22 for the pertinent holder has been activated for feeding sheets to the print engine, which causes the height of the media stack to decrease. If sheets have been fed from the stack (Y), it is checked in step S5 whether the tray has become empty. In that case the process returns to step S1. Otherwise the sensor 24 is used in step S6 for detecting the new stack height. Further, the run time is re-adjusted in step S6 by multiplying the initial run time t_r as set in step S1 by a factor (h+d) / hm, wherein h_n is the stack height that corresponds to the maximum storage capacity of the holder, h is the new stack height as measured by the sensor 24, and d is a Parameter that is adjusted such that d / h_m gives an admissible dwell time for a single sheet in the holder. If no media have been fed from the holder (N), the steps S5 and S6 are skipped.

In step S7, it is checked whether the run time, which may have been re-adjusted or not, has lapsed. If that is the case (Y), a warning signal is issued in step S8. This warning signal may for example be sent to the user interface of the printer in order to alert the user that there is a risk that the print process may be compromised. Optionally, the warning signal may also be used in the printer controller for automatically switching to another holder that holds the same media type but in which holder the media have been kept only for a shorter time. Then, a running print process may be continued until the operator has the time to replace the media that are no longer properly conditioned.

Itis observed that the process illustrated in Fig. 2 may also run when the printer is idle. In that case, the warning signal could advise the operator that the media should pre- emptively be removed and reconditioned.

When the run time has not yet lapsed in step S7 (N), the process returns to step S4, and the steps S4 to S7 are repeated in a loop until the run time has lapsed or the tray has become empty.

Fig. 3 shows an example of another routine that may be run on the media management module 30, possibly in parallel with the routines shown in Fig. 2.

In step S11, a print job is received at the printer. The control system of the printer determines the required media type and identifies the holders 12 in which sheets of this type are loaded. By way of example, it shall be assumed here that the required media type is loaded in all five holders. However, the holders may have been refilled at different times and to different amounts, so that the stack heights in the holders may be different and their time counts also differ. In step S12, the managing module reads the current time counts in the timers 28 as well asthe run times stored therein (the run times may have been updated several times in steps S6). In step S13, a time reserve is calculated for each holder 12. The time reserve is defined as the difference between the run time and the current time count and therefore indicates the time for which the media may still be kept in the holder. In step S14, the holders are sorted by rising time reserves. That means that the holders are numbered in a sequence in which the holder for which the time reserve is shortest comes first, the second holder is the one with the second shortest time reserve, and so on. Then, in step S15, the media are fed from the holders in the sort order determined in step S14. Consequently, when the print process starts, the oldest sheets will be consumed first and the youngest sheets which have been loaded only recently will be consumed last. This minimizes the risk of printing on sheets which have been stored in the holders too long.

Since the reserve times are calculated on the basis of the run times that are dependent upon the stack height, the routine also takes into account that, if two time counts are equal, for example, the media from the holder in which the stack is smallest will be consumed first.

Embodiments

1. A printer comprising a number of holders (12) for storing print media (18), and a detection system (24) configured to detect access events where an operator accesses one of the holders (12), characterized in that each holder (12) is associated with a timer (28) capable of counting the time that has passed since the holder has last been accessed.

2. The printer according to claim 1, wherein the timers (28) are configured to store adjustable run times.

3. The printer according to claim 2, comprising at least one sensor (32, 34) for detecting a climate condition in at least one of the holders, and a control system configured to adjust the run times on the basis of the detected climate conditions.

4. A method of managing print media {18) in the printer according to any of the claims 1 to 3, characterized by the steps of: - starting a timer (28) when an operator accesses a holder (12) for media (18) in the printer, the timer having a run time determined in view of an admissible maximum dwell time of the media in the holders; and - issuing a warning signal when the run time lapses.

5. The method according to claim 4, wherein the run time is determined as dependent upon at least one of the amount of media present in the holder, the volume of a storage space in the holder, and the climatic conditions in the holder.

6. The method according to claim 4 or 5, wherein the timer is started only when an operator accesses an empty holder and loads new media.

7. The method according to any of the claims 4 to 6, wherein, when media have been fed from a holder, the run time for that holder is adjusted dependent upon the amount of media remaining in that holder.

8. A method of managing print media in a printer according to any of the claims 1 to 3 that has a plurality of holders (12), characterized by the steps of: - for each holder that holds media, counting a storage duration time for which the media have been stored in the holder; - establishing a sort order for the holders, wherein the holders are sorted by increasing storage duration times; and - when media are needed for printing, feeding the media from the holders in the sort order.

9. A method of managing print media in a printer according to any of the claims 1 to 3 that has a plurality of holders (12), characterized by the steps of: - for each holder that holds media, counting a storage duration for which the media have been stored in the holder, and calculating a reserve time that depends upon the storage duration time and upon at least one of the amount of media present in the holder, the volume of a storage space in the holder, and the climatic conditions in the holder; - establishing a sort order for the holders, wherein the holders are sorted by increasing reserve times; and - when media are needed for printing, feeding the media from the holders in the sort order.

10. The printer according to any of the claims 1 to 3, comprising a media management module (30) that is configured to perform a method according to any of the claims 4 to 9.

Claims

CONCLUSIONS

A printer comprising a plurality of containers (12) for holding print media (18), and a detection system (24) configured to detect access events where an operator gains access to one of the containers (12), characterized in that each container (12) is associated with a timer (28) capable of counting the time elapsed since the container was last accessed.

The printer of claim 1, wherein the timers (28) are configured to store adjustable run times.

The printer of claim 2, comprising at least one sensor (32, 34) for detecting climatic conditions in at least one of the containers, and a control system configured to adjust the run times based on the detected climatic conditions.

A method of managing print media (18) in a printer according to any one of claims 1 to 3, characterized by the steps of: - starting a timer (28) when an operator accesses a container (12) for media (18) in the printer, the timer having a run time determined in view of an allowable maximum residence time of the media in the containers; and - an emission of a warning signal when the run time expires.

The method of claim 4, wherein the transit time is determined independently of at least one of the amount of media present in the container, the volume of a storage space in the container, and the climatic conditions in the container.

The method of claim 4 or 5, wherein the timer is only started when an operator accesses an empty container and loads new media.

The method of any one of claims 4 to 6, wherein when media is discharged from a container, the run time for said container is adjusted depending on the amount of media remaining in said container.

A method of managing print media in a printer according to any one of claims 1 to 3 having a plurality of containers (12), characterized by the steps of: - counting, for each container containing media contains a storage time period during which the media is stored in the container; - determining an order for the containers, wherein the containers are sorted by increasing storage time periods; and - outputting, when media is required for printing, said media from the containers in said order.

A method of managing print media in a printer according to any one of claims 1 to 3 having a plurality of containers (12), characterized by the steps of: - counting, for each container containing media of a storage time during which the media is kept in the container, and calculating a reserve time which depends on the storage time period and on at least one of the amount of media present in the container, the volume of a storage space in the container, and the climatic conditions in the container; - determining a sequence for the containers, wherein the containers are sorted by increasing reserve times; and - outputting, when media is required for printing, media from the containers in said order.

The printer according to any one of claims 1 to 3, comprising a media management module (30) configured to perform a method according to any one of claims 4 to 9.