EP4631735A1

EP4631735A1 - A scanning printer with an energy storing assembly

Info

Publication number: EP4631735A1
Application number: EP24169630.1A
Authority: EP
Inventors: Hermanus M. KUYPERS; Peter J.W. DONGEN; Guus M.C. PEETERS; Johannes H.L. Smeyers; Lars H.L. KORSTEN; Gijs BAKKER; Jarno G.P. ALBERS; Marvin T.F. HESSELS; Paul C. BEKKERS; Justin P.M. VAN DER VEN
Original assignee: Canon Production Printing Holding BV
Current assignee: Canon Production Printing Holding BV
Priority date: 2024-04-11
Filing date: 2024-04-11
Publication date: 2025-10-15

Abstract

A solution is provided for re-using braking energy for decelerating a printhead carriage of a scanning printer, while allowing for an adjustable scanning width (SW) for the carriage's movement. The method comprises the steps of:
- determining a scanning width (SW) proportional to a print medium's medium width (MW);
- reciprocally translating a printhead carriage (2) within the scanning width (SW) to print an image on the print medium (90);
- determining an activation position (AP) based on the scanning width (SW) and a position of the print medium (90);
- activating the energy storing assembly (30, 130) at the activation position (AP), so that energy is transferred between the energy storing assembly (30, 130) and the carriage (2).

Description

BACKGROUND OF THE INVENTION

1. Field of the invention

The invention relates to a printer and to a method of printing on a scanning printer.

2. Description of Background Art

Scanning printers, as known from e.g. JP 61037454 or US 3670861 , comprise a reciprocally movable carriage. The carriage moves back and forth in the scanning direction to swath-wise print images on a print medium. It is known to provide such printers with a braking mechanism comprising a return spring, wherein kinetic energy from decelerating the carriage is temporarily stored in the return spring, when the carriage is turning in the scanning direction. The kinetic energy is returned to the carriage to assist in its acceleration.

SUMMARY OF THE INVENTION

It is an object of the invention to provide a productive and/or low-costs scanning printer.
In accordance with the present invention, a printer according to claim 1 and a method according to claim 9 are provided.
The printer comprises:

a printhead carriage;
a drive for reciprocally moving the carriage in a scanning direction;
an energy storing assembly configured to temporarily store energy gained from decelerating the carriage and to release the energy to support accelerating the carriage.

The printer is characterized by a transport mechanism configured for moving the energy storing assembly in the scanning direction; and
a locking mechanism configured to:

allow the energy storing assembly to move with the carriage, so that no energy is transferred between the carriage and energy storing assembly in a first mode;
fix the energy storing assembly at one of a plurality of different positions of the carriage in the scanning direction, so that energy is transferred between the carriage and the energy storing assembly in a second mode.

It is the insight of the inventors that productivity of a scanning printer is improved when the length of trajectory of carriage matches the width of each individual print medium, as compared to the carriage scanning the full width of its available trajectory for each print medium. It is the further insight of the inventors that braking and driving forces for the drive driving the carriage can be reduced by allowing the energy storing assembly to move with the carriage, so that the energy storing mechanism can be activated at a respective position corresponding to the different widths of the individual print media.
In the first mode, the transport mechanism allows the energy storing assembly to move with the carriage. The first mode is applied where the carriage speed is set to be substantially constant. Substantially no energy is transferred between the energy storing assembly and the carriage. The carriage's movement is dominantly controlled by the drive. When the carriage approaches a turn, the locking mechanism is activated in the second mode to prevent at least a portion of the energy storing assembly from moving in the scanning direction. Consequently, the energy storing assembly is activated. Energy is transferred from the carriage to the energy storing assembly, thereby slowing down the carriage towards standstill. The direction of the carriage is then reversed and energy is transferred from the energy storing assembly to the carriage to assist in its acceleration. It will be appreciated that the drive may be applied to control or assist in the deceleration and/or acceleration. After transferring the energy back to the carriage, the locking mechanism disengages and the energy storing assembly is free to move with the carriage without energy transfer until the locking mechanism is activated again at the opposite turn. The transport mechanism and locking mechanism allow the energy storing assembly to be activated at different positions in the scanning direction, allowing the scanning width to be adjusted to the width of print media. This reduces the time per scan, thereby improving productivity. The braking energy re-use reduces the energy consumption of the printer. Thereby the object of the present invention has been achieved.
More specific optional features of the invention are indicated in the dependent claims.
In an embodiment, the energy storing assembly comprises two energy storing units on opposite sides of the carriage in the scanning direction, which two energy storing units are connected to the carriage, so that these move with the carriage in the first mode. At each end of the turn, the carriage is to reverse direction. To assist in braking and acceleration in both directions, energy storing units are provided on opposite sides of the carriage. The two energy storing units are preferably similar, very preferably provided substantially mirror-symmetrically with respect to each other.
In an embodiment, a single locking mechanism is provided to fix both energy storing units in the second print mode. The locking mechanism preferably engages the transport mechanism. By preventing movement of the transport mechanism, at least a portion of the energy storing units are prevented from moving in the transport direction. The carriage remains movable between the fixed portion of the energy storing units, resulting in the transfer of energy.
In an embodiment, the transport mechanism comprises a belt extending at least partially parallel to the scanning direction, wherein each energy storing unit is connected at one side to the carriage and on an opposite side to the belt. The belt allows for reciprocal movement of the energy storing assembly in a simple and compact manner. The belt may any suitable type of belt, such as a pulley, sheet belt, chain, etc. Preferably, the energy storing assembly and the belt are part of an endless loop.
In an embodiment, the belt is supported on bearings, so that the belt moves freely with the carriage in the first mode, and wherein the locking mechanism fixes the belt with respect to the bearings in the second mode. The belt is supported on low friction bearings, so that it is freely movable when the drive moves the carriage. The locking mechanism fixes the belt, for example by engaging and fixing a portion of the belt and/or by securing a bearing. The locking mechanism can then be activated to prevent movement of the belt, thereby fixing a portion of the energy storing assembly, so that energy can be transferred.
In an embodiment, each energy storing unit comprises a spring element. The spring element is arranged to deform in the second print mode, so that energy can be stored as potential spring energy. The spring constant of the spring element is suitably selected, so that it significantly contributes to the braking of the carriage in the second print mode. Any suitable spring may be applied, such as e.g. metal coil springs or other elastic materials.
In an embodiment, the printer further comprises a controller configured to determine a scanning width proportional to a width of a to be printed print medium in the scanning direction, which controller is configured to:

control the drive to maintain the movement of the carriage within the determined scanning width; and
switch the locking mechanism to the second mode, so that energy is transferred between the carriage and the energy storing assembly around turns of the carriage at and/or near the ends of the scanning width. The controller matches the scanning width to the print medium, so that the carriage does not move significantly outside of the to be printed area. The scanning width corresponds to the sum of the to be printed area and a carriage width of the print area defined by the working area of the printheads on the carriage. For example, the scanning width may be derived from a medium width of the print medium or the to be printed image, which medium width is available in a media catalogue on the controller, in the print job information, or input by the operator. At either end of the scanning width the carriage is to be decelerated and accelerated, during which moments the locking mechanism is activated to activate the energy storing assembly to transfer energy.

In an embodiment, the locking mechanism can fix the energy storing assembly at any position of the carriage in the scanning direction. Preferably, a plurality of different scanning widths can be applied. Since the energy storing assembly moves with the carriage, it can be locked at any position in the scanning direction, at least within a predetermined maximum range defined by the belt.
The present invention further relates to a method of printing on a scanning printer, comprising the steps of:

determining a scanning width proportional to a print medium's width;
reciprocally translating a printhead carriage within the scanning width to print an image on the print medium;

The method is characterized by the steps of:

determining an activation position based on the scanning width and a position of the print medium;
activating the energy storing assembly at the activation position, so that energy is transferred between the energy storing assembly and the carriage.

For different widths of print media, different scanning widths are determined and applied. At or near the end point of the scanning width in either direction in the scanning direction, an activation position is determined. This may be for example a predetermined distance from the end of scanning width or a varying distance dependent e.g. on the speed of the carriage. In between the two activation positions, the carriage moves at a substantially constant speed and substantially no energy is transferred between the carriage and the energy storing assembly. When passing an activation position, the energy storing assembly is activated. Kinetic energy from the carriage is then transferred into (potential) energy of the energy storing assembly. Thereby, the carriage slows down. At the end of the scanning width, the carriage's direction is reversed. Energy from the energy storing assembly is returned to the carriage, causing the carriage to accelerate back to its previous, constant speed. The energy storing assembly is de-activated after the energy has been transferred back to the carriage. The energy storing assembly is activated again when the carriage reaches the opposite activation position. The scanning width and the activation can be selected in correspondence with the width of the print media.
In an embodiment, the method further comprises the steps of:

determining a de-activation position based on the scanning width and a position of the print medium; and
de-activating the energy storing assembly at the de-activation position, preventing energy from transferring between the energy storing assembly and the carriage.

When the carriage passes the de-activation position, the energy storing assembly is placed in its first mode, wherein energy transfer is substantially prevented. Similar to the activation position, the de-activation position may be fixed distance from the ends of the scanning width or be dependent on the carriage's movement speeds. The activation position and de-activation position preferably have the same position in the scanning direction on either side of the scanning width. Between an de-activation position and an activation position on an opposite side of the scanning width, the energy storage assembly is its first mode, so that no substantially no energy is transferred. Between an activation position and a de-activation position on the same side of the scanning width, the second mode is applied, so that energy is transferred between the carriage and the energy storing assembly.
In an embodiment, de-activation positions are determined at opposite ends of the scanning width and the energy storing assembly moves with the carriage between the de-activation positions without substantially transferring energy. In another embodiment, the method further comprises the step of fixing the energy storing assembly between the activation position and de-activation position, so that energy is transferred back and forth between the energy storing assembly and the carriage.
In an embodiment, the step of fixing comprises activating a locking mechanism when the carriage is at the activation position, which locking mechanism prevents movement of at least a portion of the energy storage assembly in the scanning direction. When carriage is between a de-activation position and an activation position on the opposite side of the scanning width, the locking mechanism is disengaged and allows the energy storing assembly to move with the carriage, so that no energy is transferred. When the carriage is between an activation position and its corresponding de-activation position at the same respective end of the scanning width, the locking mechanism is engaged. This locally fixes the energy storing assembly, so that energy is transferred between it and the carriage.
In an embodiment, the method further comprises releasing the locking mechanism when the carriage is at the de-activation position. In between the de-activation positions, the carriage is at substantially constant speed. No energy is transferred to or from the energy storing assembly.
The invention further relates to a computer-readable storage medium comprising instructions which, when executed by a printer as described in any of the above embodiments, cause the printer to carry out the steps of the method as described in any of the above embodiments.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the present invention will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from the detailed description given herein below and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:

Fig. 1 is a schematic, perspective view of a scanning printer;
Fig. 2 is a schematic, cross-sectional view of the scanning printer in Fig. 1;
Fig. 3 is a schematic, cross-sectional view of the scanning printer in Fig. 2 in its first mode;
Fig. 4 is a schematic, cross-sectional view of the scanning printer in Fig. 2 when switching from its first mode to its second mode;
Fig. 5 is a schematic, cross-sectional view of the scanning printer in Fig. 2 in its second mode;
Fig. 6 is a schematic, cross-sectional view of the scanning printer in Fig. 2 with a smaller print medium smaller and scanning width as compared to Fig. 2;
Fig. 7 is a schematic, perspective view of a scanning printer in Fig. 2;
Fig. 8 is a schematic, perspective view of another embodiment of a scanning printer in
Fig. 1; and
Fig. 9 is a flow diagram with steps of a method for printing on the printer in Fig. 2.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with reference to the accompanying drawings, wherein the same reference numerals have been used to identify the same or similar elements throughout the several views.
Fig. 1 illustrates a scanning inkjet printer 5. A carriage 2 is provided on a support beam 7 or gantry. A drive moves the carriage 2 reciprocally in a scanning direction X along the support beam 7. One or more printheads 20 mounted on the carriage 2 swath-wise print an image on one or more print media 91, 92 positioned on a print medium support surface 1. The print medium support surface 1 is formed by means of a table 10, which comprises a suction chamber assembly (11 in Fig. 2) for sucking the print media 91, 92 against the print medium support surface 1. The carriage 2 is further movable with respect to the print medium support surface 1 in another horizontal direction Y perpendicular to the scanning direction X. In Fig. 1, the support beam 7 of the carriage 2 is moved in the other direction Y, but it will be appreciated that a print medium 91, 92 may also be moved in the other direction Y instead by means of a print medium transport system, such as transport rollers, pinches, or a transport belt. A user interface 9A is provided for interacting with the printer 5 for e.g. sending print job information. The printer 5 is provided with a controller (39 in Fig. 2), which may be connected to a processor 8A, such as a computer or other suitable device, via a connection 6 to control print operations. The processor 8A may further be connected to a network via connection N for remote control of the printer 5.
Fig. 2 illustrates the printer 5. The control 39 is connected to a suction source 12 for controlling a negative pressure in the suction chamber assembly 11. The negative pressure draws the print medium 90 against the print medium support surface 1, so that the print medium 90 is flattened and held in position. The carriage 2 is movably supported on the support beam 7 and further provided on an belt 20. The belt 32 is supported on bearings 22, which allow the belt 32 to move around the respective axes 21. The belt 32 is provided with a drive 23 for reciprocally moving the carriage 2. The drive 23 is connected to the controller 39, so that the movement of the carriage 2 in the scanning direction X can be controlled.
An energy storing assembly 30 provided to temporarily store energy from the deceleration of the carriage 2 when approaching a turn, so that said energy can be reapplied for accelerating the carriage 2 after turning. The drive 23 determines the movement of the carriage 2. The energy storing assembly 30 assists the drive 23 in decelerating and accelerating of the carriage 2. When the carriage 2 approaches an end of the scanning width SW, the energy storing assembly 30 acts as a braking mechanism. The energy storing assembly 30 comprises two energy storing units 31 in the form of spring elements on opposite sides of the carriage 2 in the scanning direction X. The two energy storing units 31 are elastically deformable, so that by deforming an energy storing unit 31 energy is temporally stored in the energy storing unit 31. By allowing the energy storing unit 31 to resume its previous state or shape, the energy can be released. The energy storing units 31 are mounted onto an belt 32, so that these can move with the carriage 2. The belt 32 with the energy storing assembly 30 forms an endless loop. The belt 32 is supported on bearings 33, which allow the belt 32 to turn around the axes 21. A locking mechanism 34 is provided for releasably fixing the belt 32, so that it can be prevented from moving in the scanning direction X. The energy storing assembly 30 moves freely with the carriage 2 until the carriage 2 approaches a turn in the scanning direction X. The locking mechanism 34 is then activated at the activation position (AP in Fig. 3), so that at least one energy storing unit 31 deforms, thereby decelerating the carriage 2 and transferring energy from the carriage 2 into the energy storing unit 31. After the velocity of the carriage 2 has become zero, the carriage 2 is accelerated into the opposite direction. This acceleration is assisted by the energy storing unit 31 releasing its stored energy back to the carriage 2. It will be appreciated that the drive 23 is controlled to accurately determine the deceleration and acceleration. However, the energy storing unit 31 provides a substantial contribution to the torque required for decelerating and accelerating the carriage 2. This reduces the requirements on the drive 23, so that a simpler and/or cheaper drive may be applied. In addition, energy consumption is reduced. The locking mechanism 34 is engaged until the carriage 2 passes the de-activation position (DP in Fig. 3), where the locking mechanism 34 is disengaged.
Fig. 3 illustrates the printer operating in the first print mode. The locking mechanism 34 is disengaged, so that the energy storing assembly 30 moves freely with the belt 32. The bearings 33 are preferably low resistance bearings 33, so that the belt 32 is able to move with little resistance. Any suitable bearing 33, such as plain bearings, ball bearings, roller bearings, etc. may be applied. The bearings 33 are provided on the same axes 21 as the bearings 22 for the carriage belt 20, which allows for a compact construction. It will be appreciated that the bearings 33 may be positioned differently. The belts 20, 32 may be formed of any suitable material, such as metal, plastic, composites, etc. in the form of a sheet, wire, chain, etc. In Fig. 3, the drive 23 is embodied as a motor, preferably an electric motor, which controls the speed of the carriage 2. In Fig. 3, the carriage speed is preferably substantially constant.
Fig. 3 illustrates that the print medium 90 has a predetermined medium width MW, which corresponds to the be printed area of the print medium 90. The carriage 2 has a certain carriage width CW, which requires the carriage 2 to move outside of the medium width MW to print on the print medium 90. The sum of the carriage width CW and the medium MW defines the scanning width SW, which is the distance the carriage 2 travels to print a single swath on the print medium 90. In the middle of the scanning width SW between a de-activation position DP and an activation position AP on the opposite end of the scanning width SW, the carriage velocity is substantially constant. The locking mechanism 34 is then disengaged, so that the energy storing assembly 30 moves freely with the carriage 2: no energy is transferred into or from the energy storing assembly 30. At the ends of the scanning width SW, the carriage 2 is decelerated and consequently accelerated to reverse the direction of the carriage 2. The deceleration starts at a predetermined activation position AP which is at the distance LW from the ends of the scanning width.
Fig. 4 illustrates the printer 5 switching from the first print mode to the second print mode. When the carriage 2 passes the activation position AP defined by the locking width LW, the locking mechanism 34 is engaged, thereby fixing the belt 32. The belt 32 is then prevented from moving in the scanning direction X. The locking mechanism 34 may be any suitable locking or braking system, such as a brake, clamp, lock, etc. The locking mechanism 34 may engage the belt 32 directly or via the bearing 33, e.g. via a cog or belt assembly. The locking mechanism 34 engages the belt 32 while the carriage 2 is in the range between the activation position AP and the dec-activation position DP on a respective side of the scanning width SW. In the example of Fig. 2, the range is illustrated by the locking width LW, though it will be appreciated that in another embodiment the activation position AP and the dec-activation position DP may have different positions in the scanning direction X.
While securing the belt 32 by the locking mechanism 34, the momentum of carriage 2 carries the carriage 2 further in the scanning direction X towards the respective end of the scanning width SW, as shown in Fig. 5. This results in the energy storing units 31 becoming deformed, thereby transferring kinematic energy from the carriage 2 into potential energy, specifically spring potential energy. In Fig. 5, the left spring element is compressed, while the right spring element is stretched. It will be appreciated that only a single spring element may also be used to store energy. The spring element may be formed of any suitable elastic material, such as metals, plastic, etc. Preferably a spring element is applied, but other energy storing units, such as fly wheels or batteries may be applied as well. In the locking width LW the carriage 2 is decelerated to a standstill at the end of the scanning width SW. The drive 23 therein controls the movement, so the position and speed of the carriage 2 are accurately controlled. Preferably, a large or major portion of the forces or torque required to decelerate the carriage 2 is applied via the energy storing units 31.
At the end of the turn in Fig. 5, the carriage 2 is accelerated in the opposite direction, as shown in Fig. 6. The stored energy in the energy storing assembly 30 is returned to the carriage 2. The deformed spring elements respectively push and pull on the carriage 2 after it has decelerated. By returning to their original shapes as in Fig. 3, the spring elements provide a force on the carriage 2 accelerating it towards the opposite end of the scanning width SW. Therein, the drive 23 may provide additional force. Passing the de-activation position DP at the locking distance LW, the carriage 2 has preferably reached its usual constant speed, and the locking mechanism 34 is disengaged. Consequently, no energy can then be transferred between the energy storing assembly 30 and the carriage 2. The energy storing assembly 30 then moves with the carriage 2, as in Fig. 3. The process in Figs. 3-6 is repeated on the opposite side of the scanning width SW. It will be appreciated the locking mechanism 34 may be engaged at different moments or distance in either direction of the carriage 2 to compensate for any energy lost in the transferring. The drive is preferably provided with a position and/or velocity sensor to determine position and/or speed of the carriage 2 to accurately control its movement.
Fig. 7 illustrates a first embodiment of the printer 5, which is similar to the embodiment in Figs. 3-6. The belt 32 is configured as a broad, flat sheet, the ends of which are joined together via the energy storing assembly 30 and the carriage 2. Fig. 8 illustrates a further embodiment of the printer 105, wherein the belt 132 is provided as a pulley. Any suitable type of belt may be applied, given that it has sufficient strength to withstand the deceleration and acceleration forces. The belt may be formed of a pulley, rope, chain, sheets, etc.
Fig. 9 illustrates the steps of a method of printing on the scanning printer 5. In step a, a print medium 90 is provided onto the print medium support surface 1 of the printer 5. The print medium 90 may be held onto the print medium support surface 1 by means of suction applied to its bottom side. The front side of the print medium 90 faces the printhead carriage 2. The print medium 90 corresponds a certain medium MW width, which is at least the width of the area to be printed on. The medium width MW is provided to the controller 39, either via the print job information or via manual input through the user interface 9A.
In step b, the controller 39 determines a scanning width SW based on the medium width MW. The scanning width SW is proportional to the medium width MW and may optionally include the carriage width CW and print job information, such as the medium width MW corresponding to an image width of the to be printed image and/or the respective size of the print medium 90. It will be appreciated that the above mentioned distances may be determined in any suitable form, such as length, widths, positions on or with respect to the print medium support surface 1, carriage position, etc.
In step c, the activation positions AP and the de-activation positions DP are determined. In the example in Fig. 2-5, these positions AP, DP are positioned at a locking distance LW from the respective ends of the scanning widths, though the positions AP, DP for activation and de-activation may also differ: the locking distance LW may different dependent on whether the carriage 2 is decelerating or accelerating. The locking distance LW may be a constant value for all print jobs, or may be adjusted in correspondence to certain print job parameters, such as the maximum or average carriage speed. The locking width LW determines a positional range in the scanning direction X wherein the locking mechanism 34 is activated. Between a de-activation position DP and its opposite activation point AP, the locking mechanism 34 is disengaged in its first mode. At each end of the scanning width SW, the locking mechanism 34 is engaged in its second mode between the respective activation position AP and the de-activation position DP.
In step d, printing is started and the drive 23 moves the carriage 2 reciprocally over the print medium 90. When outside of the locking width LW, the drive 23 maintains a substantially constant speed of the carriage 2. The locking mechanism 34 is in its first mode, so that it allows the belt 32 to move freely. This prevents the energy storing assembly 30 from absorbing or transferring energy from the carriage 2. The energy storing units 31 are in their first state, which is effectively their neutral state.
In step e, it is determined that the carriage 2 moves into the range determined by locking width LW. The locking width LW corresponds to a range wherein the carriage is decelerated from its substantially constant speed to standstill, so that the carriage 2 can be reversed in the opposite direction. As the carriage 2 enters the range of the locking distance LW by passing the activation position AP, the locking mechanism 34 in activated in step f, so that the locking mechanism 34 stops movement of the belt 32. The locking mechanism 34 directly or indirectly engages the belt 32, fixing it, so that the belt 32 is prevented from moving in the scanning direction X.
In consequence of the locking, in step g energy is transferred from carriage 2 into the energy storing assembly 30. The energy storing assembly 30 acts as a brake, which absorbs and stores kinetic energy from the carriage 2 until the carriage 2 is brought to a standstill. In the deceleration, the drive 23 may be applied to control the speed and position of the carriage 2. Immediately after standstill is carriage 2 is accelerated in the opposite direction. In step i, the stored energy is transferred back from the energy storing assembly 30 to the carriage 2, so provide an accelerating force. Also, therein the drive 23 may be applied to assist and control the movement. When the energy storing units 31 have resumed their neutral state, the locking mechanism 34 is disengaged in step j, as the carriage passes the de-activation position DP. it will be appreciated that the distance of releasing the locking mechanism 34 may at a different position of the carriage 2 than when the locking mechanism 34 was engaged. The carriage 2 thereby returns to its constant speed as in step c. Steps d-j may then be cyclically repeated until the print medium 90 has been provided with its full image. When it is determined that printing on the print medium 90 has been completed in step k, the process a-k may be repeated for a different print medium 90
Although specific embodiments of the invention are illustrated and described herein, it will be appreciated by those of ordinary skill in the art that a variety of alternate and/or equivalent implementations exist. It should be appreciated that the exemplary embodiment or exemplary embodiments are examples only and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents. Generally, this application is intended to cover any adaptations or variations of the specific embodiments discussed herein.
It will also be appreciated that in this document the terms "comprise", "comprising", "include", "including", "contain", "containing", "have", "having", and any variations thereof, are intended to be understood in an inclusive (i.e. non-exclusive) sense, such that the process, method, device, apparatus or system described herein is not limited to those features or parts or elements or steps recited but may include other elements, features, parts or steps not expressly listed or inherent to such process, method, article, or apparatus. Furthermore, the terms "a" and "an" used herein are intended to be understood as meaning one or more unless explicitly stated otherwise. Moreover, the terms "first", "second", "third", etc. are used merely as labels, and are not intended to impose numerical requirements on or to establish a certain ranking of importance of their objects.
The present invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the present invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

A printer (5) comprising :
- a printhead carriage (2);

- a drive for reciprocally moving the carriage (2) in a scanning direction (X);

- an energy storing assembly (30, 130) configured to temporarily store energy from decelerating the carriage (2) and to release the energy to support accelerating the carriage (2),
characterized by:
- a transport mechanism (40) configured for moving the energy storing assembly (30, 130) in the scanning direction (X); and
a locking mechanism (34) configured to:

- allow the energy storing assembly (30, 130) to move with the carriage (2), so that no energy is transferred between the carriage (2) and energy storing assembly (30, 130) in a first mode;

- fix the energy storing assembly (2) at one a plurality of different positions of the carriage (2) in the scanning direction (X), so that energy is transferred between the carriage (2) and the energy storing assembly (30, 130) in a second mode.
The printer (5) according to claim 1, wherein the energy storing assembly (30, 130) comprises two energy storing units (31, 131) on opposite sides of the carriage (2) in the scanning direction (X), which two energy storing units (31, 131) are connected to the carriage (2) so that these move with the carriage (2) in the first mode.
The printer (5) according to claim 2, wherein a single locking mechanism (34) is provided to fix both energy storing units (31, 131) in the second print mode.
The printer (5) according to claim 2 or 3, wherein the transport mechanism (40) comprises an endless belt (32, 132) extending at least partially parallel to the scanning direction (X), wherein each energy storing unit (31, 131) is connected one of its sides to the carriage (2) and on an opposite side to the belt (32, 132).
The printer (5) according to claim 4, wherein the belt (32, 132) is supported on bearings (33), so that the belt (32, 132) moves freely with the carriage (2) in the first mode, and wherein the locking mechanism (34) fixes the belt (32, 132) with respect to the bearings (33) in the second mode.
The printer according to claim 4 or 5, wherein each energy storing unit (31, 131) comprises a spring element.
The printer (5) according to any of the previous claims, further comprising a controller (39) configured to determine a scanning width (SW) proportional to a width of a to be printed print medium (90) in the scanning direction (X), which controller (39) is configured to:
- control the drive to maintain the movement of the carriage (2) within the determined scanning width; and

- switch the locking mechanism (34) to the second mode, so that energy is transferred between the carriage (2) and the energy storing assembly (30, 130) around turns of the carriage (2) at the ends of the scanning width (SW).
The printer (5) according to claim 7, wherein the locking mechanism (34) can fix the energy storing assembly (30, 130) at any position of the carriage (2) in the scanning direction (X).
A method of printing on a scanning printer (5), comprising the steps of:
- determining a scanning width (SW) proportional to a print medium's medium width (MW);

- reciprocally translating a printhead carriage (2) within the scanning width (SW) to print an image on the print medium (90);

- determining an activation position (AP) based on the scanning width (SW) and a position of the print medium (90);

- activating the energy storing assembly (30, 130) at the activation position (AP), so that energy is transferred between the energy storing assembly (30, 130) and the carriage (2).
The method according to claim 9, further comprising the steps of:
- determining a de-activation position (DP) based on the scanning width (SW) and a position of the print medium (90); and

- de-activating the energy storing assembly (30, 130) at the de-activation position, preventing energy from transferring between the energy storing assembly (30, 130) and the carriage (2).
The method according to claim 10, wherein de-activation positions (DP) are determined at opposite ends of the scanning width (SW) and the energy storing assembly (30, 130) moves with the carriage (2) between the de-activation positions (DP) without substantially transferring energy.
The method according to 10 or 11, further comprising the step of fixing the energy storing assembly (30, 130) between the activation position (AP) and de-activation position (DP), so that energy is transferred back and forth between the energy storing assembly (30, 130) and the carriage (2).
The method according the claim 12, the step of fixing comprises activating a locking mechanism (34) when the carriage (2) is at the activation position, which locking mechanism (34) prevents movement of at least a portion of the energy storage assembly (30, 130) in the scanning direction (X).
The method according to claim 13, further comprising releasing the locking mechanism (34) when the carriage (2) is at the de-activation position (DP).
A computer-readable storage medium comprising instructions which, when executed by a printer (5) according to any of the claims 1 to 8, cause the printer (5) to carry out the steps of the method of any of the claims 9 to 14.