A recording apparatus for forming images using a recording head includes a feeding roller, a conveying roller, a conveyance control unit, and a recording control unit. The conveyance control unit performs a conveying operation a number of times after the trailing end of a sheet reaches a predetermined position defined between the feeding roller and the conveying roller such that the trailing end of the sheet is disposed in a predetermined range upstream of the conveying roller in a sheet conveying direction after the conveying operations. At least one of the conveying operations performed a number of times is performed based on a distance from the position of the trailing end of the sheet to the position of the conveying roller.
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0. 5. A recording apparatus comprising:
a recording head configured to record an image on a sheet;
a conveying roller, disposed upstream of the recording head in a conveying direction, configured to convey the sheet;
a pinch roller configured to pinch the sheet, together with the conveying roller, at a nip portion;
a driving unit configured to drive the conveying roller by a first conveying amount, and by a second conveying amount when the trailing end of the sheet passes through the nip portion; and
an adjustment conveying unit configured to convey the sheet by an adjustment conveying amount, based on information on a position of a trailing end of the sheet such that the trailing end of the sheet stops in a predetermined area located upstream of the nip portion.
0. 1. A recording apparatus for forming images using a recording head scanning over a predetermined area on a sheet N times, the recording apparatus comprising:
a feeding roller configured to convey the sheet disposed on a stacking unit;
a conveying roller configured to further convey the sheet fed by the feeding roller;
a conveyance control unit configured to control drive of the conveying roller each time scanning is performed by the recording head; and
a recording control unit configured to control a first recording in which the scanning is performed N times by selecting recording elements of the recording head until a trailing end of the sheet reaches a predetermined position defined between the feeding roller and the conveying roller, and configured to control a second recording in which the scanning is performed N times using a part of the recording elements of the recording head after the trailing end of the sheet reaches the predetermined position,
wherein the conveyance control unit performs a conveying operation a number of times based on the value of N after the trailing end of the sheet reaches the predetermined position such that the trailing end of the sheet is disposed in a first range remote from and upstream of the conveying roller in a direction in which the sheet is conveyed after the conveying operations, and
wherein at least one of the conveying operations performed a number of times based on the value of N is performed based on a distance from a position of the trailing end of the sheet to the position of the conveying roller.
0. 2. The recording apparatus according to
0. 3. The recording apparatus according to
0. 4. A method for controlling a recording apparatus for forming images using a recording head scanning over a predetermined area on a sheet N times, the recording apparatus including a feeding roller configured to convey the sheet disposed on a stacking unit and a conveying roller configured to further convey the sheet fed by the feeding roller, the method comprising:
controlling drive of the conveying roller each time scanning is performed by the recording head; and
controlling a first recording in which the scanning is performed N times by selecting recording elements of the recording head until a trailing end of the sheet reaches a predetermined position defined between the feeding roller and the conveying roller, and controlling a second recording in which the scanning is performed N times using a part of the recording elements of the recording head after the trailing end of the sheet reaches the predetermined position,
wherein the drive of the conveying roller is controlled so as to perform a conveying operation a number of times based on the value of N after the trailing end of the sheet reaches the predetermined position such that the trailing end of the sheet is disposed in a first range including the position of the conveying roller and upstream of the conveying roller in a direction in which the sheet is conveyed after the conveying operations, and
wherein at least one of the conveying operations performed a number of times based on the value of N is performed based on a distance from a position of the trailing end of the sheet to the position of the conveying roller.
0. 6. The recording apparatus according to claim 5,
wherein the adjustment conveying amount is larger than the first conveying amount.
0. 7. The recording apparatus according to claim 5,
wherein the driving unit conveys the sheet whose trailing end is in the predetermined area by the second conveying amount.
0. 8. The recording apparatus according to claim 7,
wherein the second conveying amount is larger than the first conveying amount.
0. 9. The recording apparatus according to claim 7,
wherein the driving unit drives the conveying roller such that the trailing end of the sheet does not stop in an unstable stop area including the nip portion.
0. 10. The recording apparatus according to claim 5, further comprising:
a detection unit disposed upstream of the conveying roller in the conveying direction and configured to detect the trailing end of the sheet.
0. 11. The recording apparatus according to claim 10,
wherein the adjustment conveying unit determines the adjustment conveying amount based on the information on the position of the trailing end of the sheet detected by the detection unit.
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1. Field of the Invention
The present invention relates to recording apparatuses (e.g., ink-jet recording apparatuses) for recording (e.g., forming images) using recording heads, and relates to methods for controlling the apparatuses.
2. Description of the Related Art
Mechanisms such as ink-jet recording apparatuses that convey sheets usually include line feed (LF) rollers (conveying rollers) and eject rollers. When the mechanisms convey sheets, the LF rollers are used as main conveying units and the eject rollers are used as auxiliary conveying units.
The LF rollers are disposed upstream in a direction in which sheets are conveyed (conveying direction), and the eject rollers are disposed downstream in the conveying direction. Recording heads scan over areas between the LF rollers and the eject rollers. Therefore, areas corresponding to areas scanned by the recording heads while the sheets are engaged by the LF rollers and the eject rollers are referred to as “recording areas”.
Furthermore, areas corresponding to areas scanned by the recording heads while the sheets are engaged by only the eject rollers are also referred to as “recording areas”. That is, a recording is also made in areas adjacent to the trailing ends of the sheets.
In order to make up for a reduction in conveying accuracy during recording of the trailing ends of the sheets, a technology described in Japanese Patent Laid-Open No. 2004-230817 reduces the number of nozzles of a recording head to be used and the conveying amount of a sheet per scan when a recording is made in areas adjacent to the trailing ends of the sheet.
In Sequence (1), the conveying amount per conveying operation is small. This leads to increases in the number of times scanning is performed by the recording head and in the number of conveying operations, resulting in a reduction in throughput in recording operations.
In Sequence (2), the trailing end of the sheet stops in the unstable stop area two times. Therefore, the conveying amount in the unstable stop area becomes different from that in areas other than the unstable stop area, resulting in a reduction in image quality.
An embodiment of the present invention is directed to a recording apparatus capable of stopping the trailing end of a sheet in a predetermined range when the trailing end of the sheet passes through a conveying roller during recording.
According to an aspect of the present invention, an embodiment is directed to a recording apparatus for forming images using a recording head scanning over a predetermined area on a sheet N times. The recording apparatus includes a feeding roller configured to convey the sheet disposed on a stacking unit; a conveying roller configured to further convey the sheet fed by the feeding roller; a conveyance control unit configured to control drive of the conveying roller each time scanning is performed by the recording head; and a recording control unit configured to control a first recording in which the scanning is performed N times by selecting recording elements of the recording head until a trailing end of the sheet reaches a predetermined position defined between the feeding roller and the conveying roller, and configured to control a second recording in which the scanning is performed N times using a part of the recording elements of the recording head after the trailing end of the sheet reaches the predetermined position. The conveyance control unit performs a conveying operation a number of times based on the value of N after the trailing end of the sheet reaches the predetermined position such that the trailing end of the sheet is disposed in a first range remote from and upstream of the conveying roller in a direction in which the sheet is conveyed after the conveying operations. At least one of the conveying operations performed a number of times based on the value of N is performed based on a distance from a position of the trailing end of the sheet to the position of the conveying roller.
According to another aspect of the present invention, an embodiment is directed to a method for controlling a recording apparatus for forming images using a recording head scanning over a predetermined area on a sheet N times. The recording apparatus includes a feeding roller configured to convey the sheet disposed on a stacking unit and a conveying roller configured to further convey the sheet fed by the feeding roller. The method includes controlling drive of the conveying roller each time scanning is performed by the recording head; and controlling a first recording in which the scanning is performed N times by selecting recording elements of the recording head until a trailing end of the sheet reaches a predetermined position defined between the feeding roller and the conveying roller, and controlling a second recording in which the scanning is performed N times using a part of the recording elements of the recording head after the trailing end of the sheet reaches the predetermined position. The drive of the conveying roller is controlled so as to perform a conveying operation a number of times based on the value of N after the trailing end of the sheet reaches the predetermined position such that the trailing end of the sheet is disposed in a first range including the position of the conveying roller and upstream of the conveying roller in a direction in which the sheet is conveyed after the conveying operations. At least one of the conveying operations performed a number of times based on the value of N is performed based on a distance from a position of the trailing end of the sheet to the position of the conveying roller.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
An exemplary embodiment of the present invention will now be described in detail with reference to the drawings.
The recording apparatus forms images on sheets by, for example, repeating conveyance of the sheets by a predetermined conveying amount and scanning performed by the carriage having the recording head installed therein.
Moreover, a code wheel 362 used for detecting the conveying amount by the conveying roller 36 is disposed on the shaft of the conveying roller 36. An encoder sensor 363 for reading out marks on the code wheel 362 is disposed on a chassis adjacent to the code wheel 362. In
The drive of the conveying roller 36 is transmitted to the eject roller 40 via an idler gear 45. A code wheel 402 used for detecting the conveying amount by the eject roller 40 is disposed on the shaft of the eject roller 40, and an encoder sensor 403 for reading out marks on the code wheel 402 is disposed on the chassis adjacent to the code wheel 402.
As shown in
Next,
In
This conveying operation Fv allows the trailing end of the sheet to reliably stop in a predetermined area (predetermined range) on the conveying path having a width α located upstream of the position A in the conveying direction after the subsequent conveying operation F2 is performed four times (
When the trailing end of the sheet stops in this predetermined area (predetermined range), the trailing end of the sheet can pass through the unstable stop area and can stop in a stable stop area located downstream of the position B by conveying the sheet by a conveying amount corresponding to the distance AB+α.
Thus, the conveying operation is controlled by, for example, controlling the distance from the position of the trailing end of the sheet to the position A using the information of the encoder after the PE sensor detects the trailing end of the sheet.
The conveying sequence is not limited to that shown in
When the trailing end of the sheet that has been conveyed during the conveying operations F1a reaches the position C (or a position downstream of the position C in the conveying direction (left side)), the conveying operation F2a is performed three times, and then the conveying operation Fva is performed one time. The number of executions of the conveying operation F2a corresponds to the number of times scanning is performed by the recording head in the recording mode, i.e., three herein. Therefore, the number of executions of the conveying operation in this area becomes four in a four-pass recording mode.
The number of nozzles used for a scan (or the number of times scanning is performed over a predetermined area on the sheet) and the above-described information on the conveying amount by which the sheet is conveyed during one conveying operation for each recording mode are retained in a memory of the recording apparatus. A CPU 100 controls the recording operation and the conveying operation on the basis of the recording mode. Thus, the trailing end of the sheet can pass through the unstable stop area regardless of the recording mode.
In Step S13, it is determined whether or not the trailing end of the sheet has passed through the position C by the conducted conveying operation as shown in
On the other hand, when it is determined that the trailing end of the sheet has not passed through the position C or the conveying operation Fv has been performed in Step S13, the process proceeds to Step S15. In Step S15, the conveying amount is acquired on the basis of the information on the position of the trailing end of the sheet.
In Step S14, the distance from the position of the trailing end of the sheet to the position A is divided by a line feed amount Q, and the conveying amount during the conveying operation Fv is determined on the basis of the remainder. Instead of the above-described method in which arithmetic processing is performed, a table of information on conveying amounts can be prepared in advance. Specifically, a table of conveying amounts during the conveying operation Fv based on the distances from the positions of the trailing end of the sheet to the position A and the line feed amount Q is retained in the memory in advance. The value of the conveying amount can be acquired from this table on the basis of the information on the distance from the position of the trailing end of the sheet to the position A.
As described above, the CPU 100 controls the conveying amount and the nozzles of the recording head to be used on the basis of the information on the position of the trailing end of the sheet or on the distance from the position of the trailing end of the sheet to the position A. In order to realize the above-described control, a table of conveying amounts during the conveying operations F1, F2, F3, and Fv corresponding to the information on the positions of the trailing end of the sheet and a table of information on the number and positions of the nozzles used for recording, for example, can be prepared.
In
In
Numbers 71 to 77 each indicate a conveying operation, and the conveying operations 71 to 77 are performed in order. Moreover, the conveying amounts during the conveying operations 71 to 73 are set to 6P/16 or 5P/16. That is, when the conveying amounts during the three conveying operations 71 to 73 are 6P/16, 5P/16, and 5P/16, respectively, the total conveying amount becomes equal to the length P of the nozzle row.
As described above, after the trailing end of the sheet is detected by the PE sensor, the number of nozzles used for recording is reduced in accordance with the progress of the sheet.
In an exemplary embodiment, the number of nozzles in the nozzle row is 512, for example. When the number of nozzles to be used is limited to ¾, the number of nozzles to be used becomes 384.
In the three-pass recording, the conveying amount during one conveying operation in an area where the number of nozzles is limited (nozzle limited area) becomes P/4 (=128 nozzles).
The conveying amounts during the conveying operations 71 to 73 each correspond to that during the conveying operation F1a shown in
The processes shown in
First, a recording operation using the first to three hundred eighty-fourth nozzles in the nozzle row downstream in the conveying direction is performed (Process R1). A mark PN indicates Nth scanning by the recording head over the sheet. Next, a conveying operation by a conveying amount of Q+q is performed (Process R2). This conveying operation corresponds to the conveying operation Fv shown in
Next, a conveying operation by a conveying amount of Q is performed (Process R4). This conveying operation corresponds to the conveying operation F2 shown in
As a postscript, the position of the trailing end of the sheet is detected and the information on the distance from the position of the trailing end of the sheet to the position of the conveying roller 36 is acquired every conveying operation. The subsequent conveying operation is performed using the conveying amount based on the acquired information on the distance.
In
In this exemplary embodiment, the conveying amounts are selected from any of Q, Q+q, Q+2q, and Q+3q on the basis of the distance to the conveying roller 36 (or distance to the position A shown in
The position of the trailing end of the recording sheet when the conveying operation F3 is started can be controlled by adjusting the conveying amount during the conveying operation Fv. With this, the trailing end of the recording sheet can be reliably prevented from stopping in the unstable stop area.
Next, the above-described control flow will be briefly described. First, when the trailing end of a sheet that is being conveyed is detected by the PE sensor, the number of nozzles to be used is gradually reduced for every recording operation while the recording operations and the conveying operations are performed (for example, the number of nozzles to be used is gradually reduced to 384). After the number of nozzles is reduced to a desired value, a conveying amount during an adjustment feed is acquired on the basis of the distance from the position where (the trailing end of) the recording sheet stops to the position of the conveying roller 36. Subsequently, the conveying operation Fv (adjustment feed by the conveying amount of Q+q; see Process R2 in
According to the above-described structure, it is not necessary to reduce the conveying amount of a sheet in the nozzle limited area and the number of nozzles to be used beyond necessity. Therefore, throughput during the recording operations can be increased.
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 the priority of Japanese Application No. 2006-226701 filed Aug. 23, 2006, which is hereby incorporated by reference herein in its entirety.
Ishikawa, Tetsuya, Teshigawara, Minoru, Yanagi, Haruyuki, Onuma, Kentaro
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