RECORDING APPARATUS

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate exemplary embodiments, features, and aspects of the invention and, together with the description, serve to explain the principle of the invention.

FIG. 1 illustrates a cross section of a recording apparatus according to a first exemplary embodiment of the present invention.

FIG. 2 illustrates a cross section of a recording apparatus according to a first exemplary embodiment of the present invention.

FIGS. 3A through 3C each illustrate a separation roller using a torque limiter according to the first exemplary embodiment of the present invention.

FIGS. 4A and 4B each illustrate a drive switching mechanism provided to the recording apparatus illustrated in FIG. 1, according to the first exemplary embodiment of the present invention.

FIGS. 5A through 5D each illustrate a recording operation performed onto a recording medium by the recording apparatus illustrated in FIG. 1, according to the first exemplary embodiment of the present invention.

FIGS. 6A through 6D each illustrate a recording operation performed onto a recording medium by the recording apparatus illustrated in FIG. 1, according to the first exemplary embodiment of the present invention.

FIG. 7 illustrates a cross section of a recording apparatus according to a second exemplary embodiment of the present invention.

FIGS. 8A and 8B each illustrate a drive switching mechanism provided to the recording apparatus illustrated in FIG. 7, according to the second exemplary embodiment of the present invention.

FIGS. 9A through 9D each illustrate a state in which a recording head performs a recording operation on a preceding recording medium P1 in a main scanning direction and a recording medium is intermittently conveyed by a conveyance roller, and show operation states of each roller and transmission of drive force, according to the second exemplary embodiment of the present invention.

FIG. 10 illustrates a drive switching mechanism provided to the recording apparatus according to a third exemplary embodiment of the present invention.

FIGS. 11A through 11D each illustrate a recording operation onto a plurality of recording media that the recording apparatus performs which includes the drive switching mechanism illustrated in FIG. 10, according to the third exemplary embodiment of the present invention.

FIG. 12 illustrates an operation of a feeding unit in a conventional recording apparatus.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Various exemplary embodiments, features, and aspects of the present invention will now herein be described in detail with reference to the drawings. It is be noted that the relative arrangement of the components, the numerical expressions, and numerical values set forth in these embodiments are not intended to limit the scope of the present invention unless it is specifically stated otherwise.

First Exemplary Embodiment

Now, a first exemplary embodiment of the present invention will be described below. A recording apparatus according to the first exemplary embodiment will be described below with reference to FIGS. 1 through 4, FIGS. 5A through 5D, and FIGS. 6A through 6D.

FIGS. 1 and 2 each illustrate a cross section of the recording apparatus according to the first exemplary embodiment. FIGS. 3A through 3C each illustrate an example of a separation roller using a torque limiter. FIGS. 4A and 4B each illustrate an exemplary configuration of a drive switching mechanism provided in the recording apparatus illustrated in FIG. 1. FIGS. 5A through 5D and FIGS. 6A through 6D each illustrate a recording operation performed onto a recording medium by the recording apparatus illustrated in FIG. 1.

Referring to FIG. 1 and FIG. 2, the recording apparatus includes for the most part a feeding unit 1 and a recording unit 20. Referring to FIG. 2, the recording apparatus includes a feeding shaft 10 around which a feeding roller 11 for conveying a recording medium is supported and rotated, a separation roller 12 used for separating a recording medium, and a return lever 13 used for preventing double-feed. In addition, the recording medium includes a pressing plate 16 that presses a recording medium placed thereon against the feeding roller 11 and a pressing plate spring 17 that presses the pressing plate 16 against the feeding roller 11.

Now, an exemplary configuration of the feeding unit 1 will be described below.

The feeding unit 1 includes an automatic feeding device having a function for separating stacked recording medium, sheet by sheet, and conveying the separated recording medium into a conveyance unit. The automatic feeding device is mainly composed of a recording medium stacking unit, feeding and separation unit, and a double-feed prevention unit.

The recording medium stacking unit includes a recording medium leading edge reference portion 15a and the pressing plate 16. In a so-called standby state, in which a recording medium is not conveyed by the automatic feeding device, the pressing plate 16 is anchored at a predetermined position in a direction in which the pressing plate 16 moves away from the feeding roller 11. At this time, a clearance large enough for stacking a plurality of recording media is secured between the feeding roller 11 and the pressing plate 16. The recording medium set in this portion is retained so that a leading edge thereof abuts the recording medium leading edge reference portion 15a, under its own weight.

In the present exemplary embodiment, in order to reduce a load applied during feeding, the recording medium leading edge reference portion 15a has a rib-like shape. The pressing plate 16 rotates around its one end, and can rotate and make movement. An operation of the pressing plate 16 is restricted by the pressing plate spring 17 and a cam (not shown). A feeding operation is performed by pressing and separating the pressing plate 16 against and from the feeding roller 11 at a predetermined timing.

Now, an exemplary configuration of the feeding and separation unit will be described below.

When the pressing plate 16 is operated at a predetermined timing as described above, a bundle of recording media placed on the recording medium stacking unit is pressed against the feeding roller 11. Thus, the recording medium is pressed and the feeding roller 11 is driven to rotate at the same time. A recording medium placed on top of the recording medium bundle is conveyed by the frictional force of the feeding roller 11. Because the feeding roller 11 conveys a recording medium by its frictional force, the feeding roller 11 can be made of a rubber having a high frictional coefficient such as ethylene propylene diene monomer (EPDM) and urethane foam.

The recording apparatus according to the present exemplary embodiment includes one drive source used for conveying a recording medium. The recording apparatus conveys and feeds a recording medium while switching between a drive mode for conveying a recording medium and a drive mode for feeding a recording medium. Thus, the drive force is applied to the feeding roller 11 from the drive source via a conveyance unit and via the drive switching mechanism disposed between the drive source and the conveyance unit.

Here, the frictional force generated between the feeding roller 11 and a recording medium placed on top of the recording medium bundle is greater than the frictional force between the top-placed recording medium and a recording medium placed immediately below the top-placed recording medium. Accordingly, only the top-placed recording medium is separated and conveyed.

However, a burr can be generated at an edge portion of a recording medium when the recording medium is cut. Furthermore, recording media can be attached to each other by static electricity. Moreover, a frictional coefficient of a surface of a recording medium can be extremely large. In these cases, in order to prevent a plurality of recording media from being fed by the feeding roller 11 at a time, the separation roller 12, which is a separation unit including a torque limiter, separates only a top-placed recording medium.

The separation roller 12 is pressed against the feeding roller 11 so that the separation roller 12 abuts a recording medium downstream, in a direction of conveyance, from a point at which the feeding roller 11 and the recording medium first contact each other.

Now, an exemplary configuration of the separation roller 12 will be described below with reference to FIGS. 3A through 3C. The separation roller 12 is mounted onto a clutch cylinder 12a and fixed. The clutch cylinder 12a includes a rotatable clutch shaft 12b. A clutch spring 12c is wound around the clutch shaft 12b. One winding end of the clutch spring 12c engages with the clutch cylinder 12a.

With the above-described configuration, when the clutch shaft 12b is anchored and the separation roller 12 and the clutch cylinder 12a are rotated in a direction indicated by an arrow A in FIG. 3B, the clutch spring 12c wound onto the clutch shaft 12b is released from the clutch shaft 12b. When the separation roller 12 and the clutch cylinder 12a rotate by a predetermined angle, the clutch shaft 12b and the clutch spring 12c relatively slide. Thus, a predetermined level of torque can be maintained.

A surface of the separation roller 12 can be made of a rubber or urethane foam so as to have a coefficient of friction at a level similar to the feeding roller 11. The separation roller 12 is rotatably supported by a separation roller holder 21 (see FIG. 2), which is a separation unit supporting member. The separation roller 12 is pressed against the feeding unit 1 by a separation roller spring 26 (see FIG. 2).

With the above-described configuration, when no recording medium exists between the feeding roller 11 and the separation roller 12, the separation roller 12 is driven in accordance with the rotation of the feeding roller 11.

The frictional force between the feeding roller 11 and a recording medium is greater than the frictional force between the separation roller 12 driven at a predetermined level of torque and the recording medium. Accordingly, when one sheet of recording medium is conveyed to a portion between the feeding roller 11 and the separation roller 12, the recording medium is conveyed while the separation roller 12 is being driven.

On the other hand, when two recording media are conveyed to a portion between the feeding roller 11 and the separation roller 12, the frictional force generated between the feeding roller 11 and a recording medium on the side of the feeding roller 11 is greater than the frictional force between the recording media. In addition, in this case, the frictional force generated between the recording medium on the side of the separation roller 12 and the separation roller 12 is greater than the frictional force between the recording media.

Accordingly, the recording media can slide each other. Thus, only the recording medium on the side of the feeding roller 11 is conveyed, and the recording medium existing on the side of the separation roller 12 stays where it is and is not conveyed, while the separation roller 12 does not rotate.

Now, an exemplary configuration of the double-feed prevention unit will be described below.

As described above, when as many as two recording media are conveyed to a nip portion between the feeding roller 11 and the separation roller 12, the two recording media can be separated from each other. However, more than two recording media can be conveyed to the nip portion between the feeding roller 11 and the separation roller 12, or two recording media are conveyed to the nip portion between the feeding roller 11 and the separation roller 12 and only the recording medium on the side of the feeding roller 11 is completely conveyed out of the nip portion. In such a case, a next recording medium can be conveyed when the other recording medium still exists in the vicinity of the nip portion.

Consequently, double-feed can occur, in which a plurality of recording media is conveyed at the same time. Therefore, the double-feed prevention unit is provided.

The double-feed prevention unit includes the return lever 13. The double-feed prevention unit allows the return lever 13 to enter a recording medium conveyance path during setting of recording media or a recording standby mode, and thus prevents a leading edge of the recording medium from accidentally entering the back portion of the feeding device. The return lever 13 is released and retracts from the recording medium conveyance path after a feeding operation is started. Thus, the return lever 13 does not interfere with traveling of the recording medium during feeding of the recording medium.

Now, an exemplary configuration of the recording unit 20 will be described below.

The recording unit 20 includes a pinch roller holder 25, a pinch roller 29, a conveyance roller 30, a paper discharge roller 31, a spur 32, a recording medium edge detection sensor 39, and a carriage 5 mounted with a recording head 4. The recording unit 20 drives the carriage 5 and discharges a liquid droplet from the recording head 4 onto the recording medium, while moving the recording head 4 in a main scanning direction, so as to form an image on the recording medium fed from the feeding unit 1.

An image is formed in the above-described manner and recording media are intermittently conveyed by the conveyance roller 30 in a sub-scanning direction orthogonal to the main scanning direction. Thus, a recording operation on a recording medium is performed. The recording medium edge detection sensor 39 is capable of detecting a leading edge and a trailing edge of a recording medium. The recording medium edge detection sensor 39 can detect the dimension of the recording medium using this function.

Now, a path which transmits drive force from the conveyance roller 30 to the feeding roller 11, namely, a drive switching mechanism, will be described in detail below with reference to FIG. 4A and FIG. 4B.

The drive switching mechanism includes a solar gear 33, a swing arm 34, a planet gear 35, an arm stopper 36, and a solenoid 36a. The solar gear 33 and the planet gear 35 are connected to each other via the swing arm 34, which rotates around a rotational axis of the solar gear 33.

A friction spring (not shown) is provided between the solar gear 33 and the swing arm 34. Under the friction caused by the friction spring, the swing arm 34 oscillates in the same direction as the direction of rotation of the solar gear 33. That is, when the solar gear 33 rotates clockwise, the swing arm 34 is also oscillated clockwise. At this time, the planet gear 35 separates from a control gear 41 to be disengaged from each other. As a result, transmission of drive force to a feed roller gear 38, which is provided at one end of the feeding shaft 10, is shut off.

On the other hand, when the solar gear 33 rotates counterclockwise, the swing arm 34 is also oscillated counterclockwise. At this time, the planet gear 35 engages with the control gear 41. As a result, the drive force is transmitted to the feed roller gear 38 provided at one end of the feeding shaft 10.

As described above, the swing arm 34 oscillates according to the direction of rotation of the solar gear 33, so that switching between transmission and non-transmission of the drive force to the feed roller gear 38, namely, to the feeding roller 11 can be performed.

However, in this state, when a recording medium conveyance operation is being performed during the recording operation, that is, when the conveyance roller 30 is rotated in a direction of conveyance of a recording medium (namely, counterclockwise), the solar gear 33 rotates counterclockwise. Accordingly, with the oscillation of the swing arm 34, a drive force is transmitted to the control gear 41. As a result, a mechanism controlled by the control gear 41, for example, the pressing plate 16 and the return lever 13 undesirably continue to operate during the recording operation.

Therefore, in the present exemplary embodiment, after the feeding operation is completed and the processing shifts to the recording operation, the arm stopper 36 can be rotated by the solenoid 36a at an arbitrary timing in order to restrict the oscillation of the swing arm 34. The arm stopper 36 powers on and off the solenoid 36a. Thus, the arm stopper 36 can allow and restrict the oscillation operation of the swing arm 34.

As illustrated in FIG. 4A, when power is shut off from the solenoid 36a and a restriction surface 36b of the arm stopper 36 abuts a retaining portion 34a of the swing arm 34, the drive force is shut off. On the other hand, as illustrated in FIG. 4B, when power is supplied to the solenoid 36a and the restriction surface 36b of the arm stopper 36 is retracted from the retaining portion 34a of the swing arm 34, a drive force can be transmitted.

An operation for returning the drive switching mechanism from a state illustrated in FIG. 4B to the state illustrated in FIG. 4A after the feeding operation is completed and the processing shifts to the recording operation, is performed in a manner described below. First, the conveyance roller 30 is rotated just a little in a direction opposite to the recording medium conveyance direction. Thus, the swing arm 34 is oscillated clockwise as in FIG. 4, and the planet gear 35 is disengaged from the control gear 41. Then, power is shut off from the solenoid 36a to make the restriction surface 36b of the arm stopper 36 abut the retaining portion 34a of the swing arm 34.

Now, the recording operation performed by the recording apparatus according to the present exemplary embodiment for recording on a plurality of recording media will be described below with reference to FIGS. 5A through 5D and FIGS. 6A through 6D.

FIGS. 5A through 5D and FIGS. 6A through 6D show that a preceding recording medium P1 is subjected to the recording operation by the recording head 4 in the main scanning direction and the recording medium is intermittently conveyed by the conveyance roller 30, and shows operation states of each roller and transmission of drive force. In the schematic view illustrating each roller and the state of transmission of drive force, a roller and a gear are just partly engaged with each other. However, this is just a schematic description of the rotational direction of each component, and details of an actual configuration are different from the description.

Referring to FIGS. 5A through 5D, “P2” denotes a subsequent recording medium. The drive switching mechanism includes the solar gear 33, the swing arm 34, the planet gear 35, the arm stopper 36 including the solenoid 36a, an idler gear 37, the recording medium edge detection sensor 39, and the control gear 41.

“PL” denotes a whole length of the recording medium, and “PT” denotes a distance from a position at which a leading edge of the preceding recording medium P1 is detected by the recording medium edge detection sensor 39, to a position at which the conveyance of the recording medium P1 is completed. “PA” denotes a distance from the recording medium edge detection sensor 39 to a leading edge of the subsequent recording medium (designed distance for the recording apparatus).

As illustrated in FIG. 5A, the recording operation on the preceding recording medium P1 by the recording head 4 starts from an upper-left end of the recording medium. When the first half of main scanning in a line C1 is completed, the conveyance roller 30 performs the intermittent conveyance operation (line feed), and then the recording head 4 starts a return operation of main scanning in a line C2. This operation is repeated, and the recording head 4 performs recording on the preceding recording medium P1.

A control unit provided in the recording apparatus according to the present exemplary embodiment receives a recording command for recording on a plurality of recording media. The control unit operates the drive switching mechanism so that the subsequent recording medium P2 can be fed when the following determination expression is satisfied.

(PL−PT)<PA

where “PL” denotes the whole length of a preceding recording medium, “PT” denotes a distance corresponding to a conveyed length of the recording medium P1, and “PA” denotes a distance from the recording medium edge detection sensor 39, which has detected the leading edge of the preceding recording medium P1 to a leading edge of the subsequent recording medium.

The recording apparatus according to the present exemplary embodiment uses, as whole length “PL” of the recording medium, information included in the recording command or information obtained by the recording medium edge detection sensor 39 during the recording operation.

FIG. 5A shows that the recording operation for the return of main scanning in a line C12 is completed. In this state, the above-described determination expression is not satisfied. Accordingly, the solenoid 36a of the drive switching mechanism does not operate. Thus, the operation of the swing arm 34 is restricted by the arm stopper 36 of the drive switching mechanism.

Accordingly, when the solar gear 33 rotates counterclockwise according to the recording medium conveyance operation by the conveyance roller 30, the swing arm 34 does not similarly rotate counterclockwise as the planet gear 35 that rotates counterclockwise. Thus, the planet gear 35 does not engage with the next idler gear 37. The path for transmitting the drive force to the feeding roller 11 continues to be shut off.

FIG. 5B illustrates a state after the recording operation for the return of main scanning in the line C12 is completed and immediately before recording for the first half of the main scanning in a line C13 starts. At this time, with respect to the position of the preceding recording medium P1 in the recording apparatus, the above-described determination expression is satisfied by the line-feed operation by the conveyance roller 30 performed after the recording operation for the return of the main scanning in the line C12 is completed, and accordingly, the drive switching mechanism is permitted to operate.

That is, as can be seen from the example in FIG. 5B, a clearance equivalent to the distance expressed by “PA−(PL−PT)” is provided between the recording medium P1 and the recording medium P2. Accordingly, after the recording for the first half of main scanning in the line C13 is completed and before the line-feed operation is performed by the conveyance roller 30, the solenoid 36a releases the arm stopper 36, and thus the solar gear 33 rotates clockwise in FIG. 5B according to the recording medium conveyance operation by the conveyance roller 30.

Accordingly, the swing arm 34 is oscillated clockwise in FIG. 5B, the planet gear 35 engages with the control gear 41, and the feeding roller 11 can be driven.

The drive switching mechanism is shifted to the above-described state, and the line-feed operation is performed by the conveyance roller 30 after the recording in the first half of the main scanning in the line C13 is completed, so that the feeding roller 11 is driven as illustrated in FIG. 5C. Thus, the line-feed operation for the preceding recording medium P1 and the feeding operation for the subsequent recording medium P2 are performed in cooperation with each other.

In the recording apparatus according to the present exemplary embodiment, the conveyance roller and the feeding roller are driven by one drive source as described above. Thus, the feeding operation illustrated in FIG. 5C and FIG. 5D is intermittently performed in cooperation with the intermittent conveyance operation by the conveyance roller 30.

Now, another case will be described below with reference to FIGS. 6A through 6D in which the transmission of the drive force to the feeding roller 11 is started at another different timing. In the case of the recording operation illustrated in FIGS. 6A through 6D, a margin in the recording medium on a leading edge side is larger than the example illustrated in FIGS. 5A through 5D.

As illustrated in FIG. 6A, the recording operation on the preceding recording medium P1 performed by the recording head 4 starts from the upper-left corner of the recording medium, just as the example illustrated in FIGS. 5A through 5D. When the first half of the main scanning in a line C1 is completed and then the intermittent conveyance operation (line-feed operation) is performed by the conveyance roller 30, the recording head 4 starts a recording operation for return of main scanning in a line C2. The recording head 4 repeats this operation to perform recording on the preceding recording medium P1.

FIG. 6A shows that the recording operation for the first half of the main scanning in a line C11 is completed. In this state, the above-described determination expression “(PL−PT)<PA” is not satisfied. Accordingly, the solenoid 36a in the drive switching mechanism does not operate.

Thus, the operation of the swing arm 34 is restricted by the solenoid 36a of the arm stopper 36 in the drive switching mechanism. Accordingly, when the solar gear 33 rotates counterclockwise in accordance with the recording medium conveyance operation by the conveyance roller 30, the swing arm 34 does not similarly rotate counterclockwise as the planet gear 35 rotates counterclockwise.

Thus, the planet gear 35 does not engage with the next idler gear 37. Therefore, the path for transmitting the drive force to the feeding roller 11 continues to be shut off.

FIG. 6B illustrates a state after the recording operation for the first half of main scanning in the line C11 is completed and immediately before recording for the return operation of the main scanning in the line C12 starts. At this time, with respect to the position of the preceding recording medium P1 in the recording apparatus, the above-described determination expression is satisfied by the line-feed operation performed by the conveyance roller 30 after the recording operation for the return of the main scanning in the line C11 is completed, and accordingly, the drive switching mechanism is permitted to operate.

That is, as can be seen from the example in FIG. 6B, a clearance equivalent to the distance expressed by “PA−(PL−PT)” is provided between the recording medium P1 and the recording medium P2. Accordingly, after the recording for the return operation of the main scanning in the line C12 is completed and before the line-feed operation is performed by the conveyance roller 30, the solenoid 36a releases the arm stopper 36, and thus the solar gear 33 rotates clockwise in FIG. 6B in accordance with the recording medium conveyance operation by the conveyance roller 30.

Accordingly, the swing arm 34 is oscillated clockwise in FIG. 6B, the planet gear 35 engages with the control gear 41, and the feeding roller 11 can be driven via the feed roller gear 38.

The drive switching mechanism is shifted to the above-described state, and the line-feed operation is performed by the conveyance roller 30 after the recording for the return main scanning in the line C12 is completed, so that the feeding roller 11 is driven as illustrated in FIG. 6B. Thus, the line-feed operation for the preceding recording medium P1 and the feeding operation for the subsequent recording medium P2 are performed in cooperation with each other.

Just as described above with reference to FIGS. 5A through 5D, the feeding operation illustrated in each of FIG. 6C and FIG. 6D is intermittently performed in cooperation with the intermittent conveyance operation by the conveyance roller 30.

When the above-described operation is performed, the conveyance roller 30 and the feeding roller 11 are driven with one drive source in the recording apparatus, so that the clearance between the preceding recording medium P1 and the subsequent recording medium P2 can be made small. Thus, time taken for recording can be significantly shortened.

Meanwhile, if the arm stopper 36 remains released when the above-described feeding operation is completed, mechanical portions controlled by the feeding roller 11 and the control gear 41 are undesirably driven during the recording operation. In order to prevent this, as described above with reference to FIGS. 4A and 4B, the conveyance roller 30 is rotated just a little in a direction opposite to the recording medium conveyance direction.

Thus, the swing arm 34 is oscillated clockwise in FIGS. 4A and 4B, so as to disengage the planet gear 35 from the control gear 41. Then, power is shut off from the solenoid 36a so as to make the restriction surface 36b of the arm stopper 36 abut the retaining portion 34a of the swing arm 34.

Thus, when the swing arm 34 starts to oscillate counterclockwise in FIG. 4A and FIG. 4B in accordance with the rotation of the conveyance roller 30 in the recording medium conveyance direction, that is, in accordance with the counterclockwise rotation operation illustrated in FIG. 4A and FIG. 4B, the planet gear 35 does not engage with the control gear 41. Thus, transmission of the drive force to the feeding roller 11 is shut off.

Second Exemplary Embodiment

Now, a second exemplary embodiment of the present invention will be described below. FIG. 7 illustrates a cross section of the recording apparatus according to the second exemplary embodiment. In the present exemplary embodiment, as illustrated in FIG. 7, the recording apparatus includes a trigger arm 40, instead of the arm stopper 36 having the solenoid 36a in the first exemplary embodiment.

A control gear 41 controls an operation of the mechanical portions of a feeding device. In the present exemplary embodiment, a drive force is transmitted to the feeding roller 11 via the control gear 41. Note that components and portions in the present exemplary embodiment having the same functions as the first exemplary embodiment are provided with the same reference numerals and symbols. Accordingly, a description is not repeated here.

FIGS. 8A and 8B illustrate an exemplary configuration of a drive switching mechanism provided in the recording apparatus illustrated in FIG. 7. As illustrated in FIG. 8A and FIG. 8B, the trigger arm 40 includes an operation surface 40a abutting a surface of a cam (not shown) provided in the carriage 5, and a restriction surface 40b for restricting oscillation of the swing arm 34.

The operation surface 40a of the trigger arm 40 is pressed downward by the cam surface of the carriage 5 (not shown) mounted with the recording head 4, at a specific position of the recording head 4 in the main scanning direction. Thus, the trigger arm 40, just as the arm stopper 36 (see FIG. 4), can allow and restrict the oscillation operation of the swing arm 34.

Within a range in which the carriage 5 mounted with the recording head 4 operates in an ordinary recording area in the main scanning direction, the operation surface 40a of the trigger arm 40 does not contact the cam surface (not shown) of the carriage 5. Accordingly, as illustrated in FIG. 8A, the restriction surface 40b of the trigger arm 40 abuts the retaining portion 34a of the swing arm 34 so as to restrict the oscillation of the swing arm 34.

That is, when the solar gear 33 rotates counterclockwise in FIG. 8A, the swing arm 34 does not oscillate due to restriction by the restriction surface 40b. Thus, the planet gear 35 does not engage with the control gear 41.

On the other hand, when the carriage 5 moves to a predetermined position, the operation surface 40a of the trigger arm 40 is pressed downward by the cam surface (not shown) of the carriage 5. Then, the restriction surface 40b is disengaged from the retaining portion 34a of the swing arm 34. In this state, the swing arm 34 can oscillate.

That is, when the solar gear 33 rotates counterclockwise in FIG. 8A, the swing arm 34 oscillates counterclockwise. Thus, the planet gear 35 engages with the control gear 41, and the drive force is transmitted to the feeding roller 11 via the feed roller gear 38.

An operation for returning the drive switching mechanism from a state illustrated in FIG. 8B to the state illustrated in FIG. 8A after the feeding operation is completed and the processing shifts to the recording operation, is performed in a manner described below.

First, the conveyance roller 30 is rotated just a little in a direction opposite to the recording medium conveyance direction. Thus, the swing arm 34 is oscillated clockwise as in FIG. 4, so as to disengage the planet gear 35 from the control gear 41. Then, the carriage 5 is moved to a position at which the operation surface 40a of the trigger arm 40 is not pressed downward, so as to make the restriction surface 40b of the trigger arm 40 abut the retaining portion 34a of the swing arm 34.

As described above, the recording apparatus according to the present exemplary embodiment utilizes the oscillation of the swing arm 34 and the operation of the trigger arm 40 to switch between the modes for transmitting the drive force to the feeding roller 11.

Note that the specific position of the carriage 5 in the main scanning direction at which drive transmission mode is switched, is located outside the recording area in which the recording operation is performed on the recording medium. Accordingly, when the feeding operation starts by switching the drive force transmission mode, it is necessary to move the recording head 4 outside the recording area in the main scanning direction.

In the present exemplary embodiment, in order to reduce manufacturing costs of the recording apparatus to a minimum, the trigger arm 40 is provided only on one end of the recording medium. Accordingly, depending on image patterns to be recorded, the timing for starting feeding of the subsequent recording medium P2 delays by time of one main scanning.

Now, the operation performed in this case will be described with reference to FIGS. 9A through 9D.

FIGS. 9A through 9D show a state in which a preceding recording medium P1 is subjected to the recording operation by the recording head 4 in the main scanning direction and the recording medium is intermittently conveyed by the conveyance roller 30, and also show operation states of each roller and transmission of drive force. In the schematic view illustrating each roller and the state of transmission of drive force, a roller and a gear are just partly engaged with each other. However, this is just a schematic description of the rotational direction of each component, and details of an actual configuration are different from this description.

Referring to FIGS. 9A through 9D, “P2” denotes a subsequent recording medium. The drive switching mechanism includes the solar gear 33, the swing arm 34, the planet gear 35, the idler gear 37, the recording medium edge detection sensor 39, and the control gear 41.

“PL” denotes the whole length of the recording medium, and “PT” denotes a distance from a position at which a leading edge of the preceding recording medium P1 is detected by the recording medium edge detection sensor 39, to a position at which the conveyance of the recording medium P1 is completed. “PA” denotes a distance from the recording medium edge detection sensor 39 to a leading edge of the subsequent recording medium (design distance for the recording apparatus).

As illustrated in FIG. 9A, the recording operation on the preceding recording medium P1 by the recording head 4 starts from an upper-left end of the recording medium, just as in the first exemplary embodiment. When an operation for the first half of main scanning in a line C1 is completed, the conveyance roller 30 performs the intermittent conveyance operation (line feed), and then the recording head 4 starts a recording operation for the return of main scanning in a line C2. This operation is repeated so that the recording head 4 performs recording on the preceding recording medium P1.

(PL−PT)<PA

where “PL” denotes the whole length of a preceding recording medium, “PT” denotes a distance corresponding to conveyed length of the recording medium P1, and “PA” denotes a distance from the recording medium edge detection sensor 39, which detects the leading edge of the preceding recording medium P1, to a leading edge of the subsequent recording medium.

If the above-described determination expression is not satisfied, the operation of the swing arm 34 is restricted by the operation of the trigger arm 40, which is the drive switching mechanism. Accordingly, when the solar gear 33 rotates clockwise in FIGS. 9A through 9D in accordance with the recording medium conveyance operation by the conveyance roller 30, the swing arm 34 does not rotate clockwise in FIGS. 9A through 9D the same as the planet gear 35 that rotates clockwise. Thus, the planet gear 35 does not engage with the next control gear 41. Thus, the path for transmitting the drive force to the feeding roller 11 continues to be shut off.

FIG. 9A illustrates a state after the recording operation for the return of the main scanning in the line C12 is completed and immediately before recording for the first half of the main scanning in a line C13 starts. At this time, the position of the preceding recording medium P1 in the recording apparatus satisfies the above-described determination expression.

That is, as can be seen from the example in FIG. 9A, a clearance equivalent to the distance expressed by “PA−(PL−PT)” is provided between the recording medium P1 and the recording medium P2. Thus, the drive switching mechanism is permitted to operate.

In the first exemplary embodiment, a drive force can be transmitted to the feeding roller 11 by switching the drive mode at this timing. In the present exemplary embodiment, because the trigger arm 40 is provided only at one end of the recording medium, the drive force can be transmitted to the feeding mechanism only during the return operation for the main scanning (even-number-of-time-th recording operation).

Accordingly, if the above-described determination expression is satisfied, when the operation of the recording head 4 is main scanning in the direction in which the recording head 4 is disengaged from the trigger arm 40, the drive force is transmitted in the following manner. After the main scanning by the recording head 4 is completed and the conveyance roller 30 has performed the line-feed operation, the trigger arm 40 is operated in the direction opposite to the main scanning direction, so as to transmit the drive force to the feeding roller 11. FIG. 9 illustrates the state of this operation.

When the recording operation for the return of main scanning in a line C14 is started in an ordinary recording operation, the speed of moving the carriage 5 is reduced immediately after the recording is completed, and then a next main scanning is performed.

However, in the case where the drive force is transmitted using the drive switching mechanism, that is, when it is necessary to operate the trigger arm 40 by the carriage 5 mounted with the recording head 4, the carriage 5 is operated as follows. As illustrated in FIG. 9B, the moving speed of the carriage 5 is not immediately reduced, and the carriage 5 is moved to a target stopping position at which the trigger arm 40 is located. The target stopping position is located outside the range of the ordinary recording operation.

When the conveyance roller 30 performs the line-feed operation in a state where the recording for the first half of the main scanning in the line C14 is completed and the carriage 5 operates the trigger arm 40, the restriction surface 40b of the trigger arm 40 disengages from the retaining portion 34a of the swing arm 34. In this state, the swing arm 34 can oscillate. That is, when the solar gear 33 rotates counterclockwise in FIG. 9B, the swing arm 34 oscillates counterclockwise in FIG. 9B. Thus, the planet gear 35 engages with the control gear 41, and the drive force is transmitted to the feeding roller 11 via the feed roller gear 38.

When the drive switching mechanism shifts to the above-described state, and the line-feed operation is performed by the conveyance roller 30 after the recording for the return operation of the main scanning in the line C13 is completed, the feeding roller 11 is driven as illustrated in FIG. 9C. Thus, the line-feed operation for the preceding recording medium P1 and the feeding operation for the subsequent recording medium P2 are performed in cooperation with each other.

In the recording apparatus according to the present exemplary embodiment, just as the first exemplary embodiment, the conveyance roller 30 and the feeding roller 11 are driven by one drive source as described above. Thus, the feeding operation in the state illustrated in each of FIG. 9C and FIG. 9D is intermittently performed in perfect cooperation with the intermittent conveyance operation by the conveyance roller 30.

In the configuration of the first exemplary embodiment, depending on image patterns to be recorded, the timing for starting feeding of the subsequent recording medium P2 delays by a time equivalent to one main scanning.

On the other hand, in the present exemplary embodiment, the above-described operation is performed in the recording apparatus in which the conveyance roller 30 and the feeding roller 11 are driven by one drive source so that the clearance between the preceding recording medium P1 and the subsequent recording medium P2 can be made small. Thus, the time taken for recording can be significantly shortened.

Furthermore, in the present exemplary embodiment, the manufacturing cost of the recording apparatus can be reduced.

Meanwhile, if the trigger arm 40 remains released when the above-described feeding operation is completed, mechanical portions controlled by the feeding roller 11 and the control gear 41 are undesirably driven during the recording operation. In order to prevent this, as described above with reference to FIGS. 8A and 8B, the conveyance roller 30 is rotated just a little in a direction opposite to the recording medium conveyance direction.

Thus, the swing arm 34 is oscillated clockwise in FIGS. 8A and 8B, so as to disengage the planet gear 35 from the control gear 41. Then, power is shut off from the solenoid 36a to make the restriction surface 36b of the arm stopper 36 abut the retaining portion 34a of the swing arm 34. Then, the carriage 5 is moved to a position at which the operation surface 40a of the trigger arm 40 is not pressed downward, so as to make the restriction surface 40b of the trigger arm 40 abut the retaining portion 34a of the swing arm 34.

Thus, when the swing arm 34 starts to oscillate counterclockwise in FIG. 8A and FIG. 8B in accordance with the rotation of the conveyance roller 30 in the recording medium conveyance direction, that is, in accordance with the counterclockwise rotation operation illustrated in FIG. 8A and FIG. 8B, the planet gear 35 does not engage with the control gear 41. Thus, transmission of the drive force to the feeding roller 11 is shut off.

Third Exemplary Embodiment

Now, a third exemplary embodiment of the present invention will be described below. FIG. 10 illustrates an exemplary configuration of the drive switching mechanism provided in the recording apparatus according to the third exemplary embodiment.

Referring to FIG. 10, the drive switching mechanism includes a spring 45, a retaining pawl 47, a ratchet 51, an engagement protrusion 55, and a clutch pawl 58. The retaining pawl 47 is pressed against a gear G3 by the spring 45, and thus functions as a friction clutch.

When the conveyance roller 30 is rotated in a direction opposite to the recording medium conveyance direction, that is, when the conveyance roller 30 is rotated clockwise in FIG. 10, the gear G3 rotates counterclockwise in FIG. 10. Together with the rotation, the retaining pawl 47 is rotated by the friction clutch counterclockwise as shown in FIG. 10.

Then, the retaining pawl 47 is disengaged from the engagement protrusion 55. Thus, the ratchet 51 engages with the clutch pawl 58. In this state, when the conveyance roller 30 is rotated in the recording medium conveyance direction, that is, counterclockwise in FIG. 10, the drive force is transmitted to the feeding roller 11 due to the engagement between the ratchet 51 and the clutch pawl 58.

As illustrated in FIG. 11A, the recording operation on the preceding recording medium P1 by the recording head 4, starts from an upper-left end of the recording medium, just as in the first and the second exemplary embodiments. When an operation for the first half of main scanning in a line C1 is completed, the conveyance roller 30 performs the intermittent conveyance operation (line feed), and then the recording head 4 starts a recording operation for return of main scanning in a line C2. This operation is repeated so that the recording head 4 performs recording on the preceding recording medium P1.

In this state, the ratchet 51 does not engage with the clutch pawl 58. Thus, the path for transmitting the drive force to the feeding roller 11 continues to be shut off.

FIG. 11A illustrates a state after the recording operation for the return of main scanning in the line C12 is completed and recording for the first half of main scanning in a line C13 has started. At this time, with respect to the position of the preceding recording medium P1 in the recording apparatus, the determination expression “(PL−PT)<PA” is satisfied, just as the second exemplary embodiment illustrated in FIGS. 9A through 9D.

In the present exemplary embodiment, if the recording medium is conveyed in an opposite direction in this state, a trailing edge of the preceding recording medium P1 and a leading edge of the subsequent recording medium P2 can collide with each other. Accordingly, in the present exemplary embodiment, even when the above-described determination expression is satisfied, the ordinary line-feed operation is performed as illustrated in FIG. 11B, so as to perform a recording operation for the return of main scanning in the line C14.

When the recording operation for the return of main scanning in the line C14 is completed, the conveyance roller 30 conveys the preceding recording medium P1 by a distance “PC” in an opposite direction, as illustrated in FIG. 11C. Then, the retaining pawl 47 is disengaged from the engagement protrusion 55 by the friction clutch in the drive switching mechanism. Thus, the ratchet 51 engages with the clutch pawl 58, and the drive force is transmitted to the feeding roller 11.

Then, as illustrated in FIG. 11D, the conveyance roller 30 conveys the recording medium in a forward direction in a length equivalent to a sum of the distance PC, in which the recording medium is conveyed in the opposite direction in the state in FIG. 11C, and a distance in a next line-feed operation. Thus, the recording medium P1 is positioned where the recording operation for the return of main scanning in a line C15 is performed and the operation for feeding the recording medium P2 starts.

In the recording apparatus according to the present exemplary embodiment, just as in the first and the second exemplary embodiments, the conveyance roller and the feeding roller are driven by one drive source as described above. Thus, the feeding operation in the state illustrated in FIG. 11D is intermittently performed in cooperation with the intermittent conveyance operation by the conveyance roller 30.

When the above-described feeding operation is completed, the retaining pawl 47 of the drive switching mechanism according to the present exemplary embodiment engages with the engagement protrusion 55 again. Thus, the ratchet 51 disengages from the clutch pawl 58. The transmission of the drive force to the feeding roller 11 is shut off. Accordingly, the feeding roller 11 is not driven during the recording operation.

As described above, according to each exemplary embodiment of the present invention, the recording apparatus can be realized whose manufacturing cost is sufficiently low and which can reduce time taken for recording.

While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications, equivalent structures, and functions.

This application claims priority from Japanese Patent Application No. 2006-146717 filed May 26, 2006, which is hereby incorporated by reference herein in its entirety.

RECORDING APPARATUS

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