This application claims priority under 35 USC ยง119 to Japanese Patent Application Nos. 2005-009240 and 2005-283838, filed on January 17 and September 29, both 2005, the entire contents of which are hereby incorporated by reference.
A portion of the disclosure of this patent document contains material, which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
1. Field of the Invention
The present invention relates to a printing apparatus capable of executing duplex printing, and in particular to a printing apparatus creating a drying time for drying ink on a front side of a printing sheet.
2. Discussion of the Background art
In an ink jet printing apparatus capable of executing duplex printing on both sides of a printing sheet, it is known that a user manually inverts a printing sheet after printing an image on a front side surface. Specifically, when a duplex printing mode is designated, a plurality of printing sheets are launched from a sheet feed tray and images of odd number pages are firstly printed onto front side surfaces of the plurality of printing sheets.
Then, the printing sheets with odd number page images are set to the sheet feed tray by the user, and are launched and receive even number page printings on their rear sides. When images are to be printed on more than three pages of the printing sheets, printing of even number page images starts when all of the odd number page images have been printed.
According to such an ink jet printing apparatus, the printing sheet is stained by a friction of a feed roller that pressure contacts the surface of the printing sheet. Also, stein of a sheet feed pad and that caused during a transfer process spread to the printing sheet. In view of these, Japanese Patent Application Laid Open Nos. 2003-226060, and 2203-320727 attempt to suppress these steins.
Specifically, printing data of first and second risky regions of a front side surface to be printed are compared with each other. Then, printing data of a rear side surface is outputted without being inverted when an amount of printing data of the first risky region is smaller than that of the second risky region.
Whereas printing data is inverted and outputted when an amount of printing data of the second risky region is smaller than that of the first risky region. Further, the rear side surface is fed in the same direction as the front side surface when the amount of printing data of the first risky region is smaller than that of the second risky region. The rear side surface is fed in the opposed direction to that of the front side surface when the amount of printing data of the second risky region is smaller than that of the first risky region. As a result, the above-mentioned steins are suppressed.
Accordingly, an object of the present invention is to improve such background arts and provides a new and novel duplex printing apparatus including a printing head that prints an image on a printing sheet, a conveying device that skips a blank portion of the printing sheet at a prescribed speed, and a comparison device that compares skip suppression information with a prescribed threshold. A speed changing device is provided to decrease the prescribed speed in accordance with a comparison result of the comparison device.
In another embodiment, the prescribed skip suppression information represents a distance of the blank portion.
In yet another embodiment, a total ink amount calculation device is provided to calculate a total amount of ink to be used in a printing page. The prescribed skip suppression information represents the total ink amount.
In yet another embodiment, an ink amount accumulating device is provided to accumulate an amount of ink used in printing in a main scanning direction.
In yet another embodiment, a determination device is provided to determine if printing is executed to a front or rear side surface of the printing sheet. The speed changing device decreases the prescribed speed in accordance with a determination result of the determination device.
In yet another embodiment, the prescribed threshold is assigned to front and rear side surfaces of the printing sheet. The prescribed threshold for the rear side surface is lower than that of the front side surface.
A more complete appreciation of the present invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
Referring now to the drawing, wherein like reference numerals designate identical or corresponding parts throughout several views. An ink jet printer sometimes includes a printing sheet inversion mechanism or path for executing duplex printing.
A plain paper of a printing sheet generally needs a prescribed time period to dry ink carried thereon. In particular, when the second surface is printed before the first surface sufficiently dries, and the printing sheet passes through the inversion path, an image is damaged by a friction of a conveyance roller or blurs on the second surface.
On the other hand, when a printing head is moved in a main scanning direction and an image does not exist continuously in a sub scanning direction, a printing sheet is preferably moved to a position of the next image without printing as a skipping operation.
According to one embodiment of the present invention, such a skipping operation is restricted in a prescribed manner as mentioned later in detail. For example, the maximum of a skipping length is restricted in a prescribed level and a length skipping length is divided more than twice to skip. Thus, an average line speed of a printing sheet is decreased. Thereby, an ink drying time is sufficiently created.
Now, an exemplary ink jet printer of one embodiment of the present invention is described with reference to
Upon reaching, the sheet P is conveyed by the conveyance belt 13. A plurality of heads 6 for cyan, yellow, magenta, and black colors are arranged and execute printings above a flat surface of the conveyance belt 13. A horizontal conveyance roller and a spur 14 cooperatively convey the sheet P after the printing. When a time needed for drying ink has elapsed, a switching pick changes a path for the sheet P either to the sheet ejection section 4 or the duplex section 5. When a simplex printing is to be executed, the sheet P is fed to an sheet ejection roller 15, and is then inverted and ejected onto the sheet ejection section 4 while inclining the switching pick to a solid line side. When a duplex printing is to be executed, the sheet P is fed to an inversion roller 16 and is inverted while inclining the switching pick 8 to a dotted line side. The sheet P then advances to the registration roller 18 again through a path extending over a duplex sheet feeding roller 17 and a vertical conveyance roller 12 included in the duplex section 5. After that, a rear side surface receives an image in the same manner as the front side surface. After image formation to the rear side surface is completed, the separation pick 8 is inclined again to the solid line side, and the sheet is fed toward the sheet ejection roller 15 and is ejected onto the sheet ejection section 4.
Now, an exemplary large capacity ink cartridge, a head, and a substitute tank included in an ink jet printer are described with reference to
When it is determined that the large capacity ink cartridge 20 is emptied, such an effect is displayed on a display section (not shown) so as to urge a user to replace the old large capacity ink cartridge 20 to a new. Since the substitute tank 21 is emptied after execution of a prescribed amount of printing with a prescribed density for a prescribed amount of data, a carriage 30 advances to a filling work position. That is, a sensor (not shown) is arranged to confirm an amount of ink remaining in the substitute tank 21. Further, a suction mechanism (not shown) is arranged so as to avoid clogging of the head 6. Those devices are arranged so that the head 6 can be cleaned, ink can be discharged as a trial to prevent a head 6 not used for a long time from clogging, and a prescribed mechanism (not shown) can wipe the head 6 when the ink is filled at the filling work position.
An exemplary printing of a head 6 onto a sheet P is now described with reference to
An exemplary control section of the ink jet printer 1 is now described with reference to
Further, the control section includes a network control unit (NCU) 50 that is connected to a personal computer and receives data of printing and controlling.
Image data is externally received from a personal computer via the NCU 50, and is temporarily stored in an image data use RAM 53. Then, the image data is converted to printing data by the CPU 41, and is stored in the HDD 52 controlled by a HDD controller 51. Then, the image data stored in the HDD 52 is read by the HDD 52 and is inputted into a write control section 60 at a prescribed time in synchronism with a conveyance of the sheet P. The print control section 60 converts and executes discharging of ink from the head 6 in accordance with the image data input, thereby printing an image on the sheet P.
An exemplary operation of an ink jet printer 1 according to one embodiment of the present invention is described with reference to
An exemplary sequence of determining if a conveyance length (i.e., a skipping length) is to be divided is now described with reference to
Specifically, if the skip suppression flag is turned off (i.e., No, in step S200), a sheet is fed as it is in step S203. Further, if the skip suppression flag is turned on (i.e., Yes, in step S200), it is further determined if a conveyance amount is more than a prescribed threshold in step S201. The conveyance amount may be compared with a prescribed threshold to determine if the former exceeds the latter. If it is negative (i.e., No, in step S201), the sheet is fed as it is in step S203. In contrast, if it is positive (i.e., Yes, in step S201), the conveyance length is shortened and the sheet P is intermittently fed in steps S202 and S203.
Now, another exemplary skipping suppression operation executed based on an amount of ink to be spent is described with reference to
If the decision is positive (i.e., Yes, in step S300), the total amount of ink to be used in printing on a page is calculated in step S301. Such calculation is executed based on image data read by the write control section 60 from the HDD 52.
Then, the calculated total ink amount is compared with a previously set threshold of an ink usage amount in step S302. If the former does not exceed the latter, accordingly the comparison result is negative (i.e., No, in step S302), a skip suppression flag is turned off in step S304. If the comparison result is positive (i.e., Yes, in step S304), the flag is turned on in step S303.
Now, an exemplary sequence of starting the skip suppression is described with reference to
If the accumulated ink amount does not exceed the threshold, accordingly, comparison result is negative (i.e., No, in step S401), the process is terminated as is. If the comparison result is positive (i.e., Yes, in step S401), the skip flag is turned on (in step S402).
When the write control section 60 completes the printing activity, information of the usage ink amount is cleared, and the skip suppression flag is turned off as shown in step S500 of
Now, an exemplary sequence of determining if a current printing page is either a first or second surface is described with reference to
Initially, it is determined if the duplex printing is executed (in step S600). For example, when a user designate a printing mode through am operation control section 10, the CPU 41 determines the mode based on the designation. If the determination is negative (i.e., No, in step S600), the process is terminated as it is. If the determination is positive (i.e., Yes, in step S600), it is further determined if the current printing page is the second surface in step S601.
A determination as a simplex printing can be made by detecting if a simplex printing is designated or a sheet P is conveyed from the sheet feeding section 2 to a registration sensor 9. A determination as a duplex printing can be made by detecting if a sheet P is conveyed from the duplex section 5. Further, a determination as a simplex printing can be made by detecting id a sheet P is fed from the sheet feeding section 2 while the sheet ejection section 4 is its ejection destination.
If the current printing page is the second surface (i.e., Yes, in step S601), the process is terminated as it is. If the current printing page is not the second surface (i.e., No, in step S601), the skip suppression is executed (in step S602).
Now, an exemplary sequence of changing a threshold for determining necessity of skipping suppression is described with reference to
Numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the present invention may be practiced otherwise that as specifically described herein.
Number | Date | Country | Kind |
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2005-009240 | Jan 2005 | JP | national |
2005-283838 | Sep 2005 | JP | national |
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