1. Field of the Invention
The present invention relates to a printing apparatus which prints images on a plurality of sheets and, more particularly, a printing apparatus which executes a maintenance operation between the completion of printing on a preceding sheet and the start of printing on a succeeding sheet.
2. Description of the Related Art
Japanese Patent Laid-Open No. 2009-241261 describes an inkjet printing apparatus which executes preliminary discharge immediately before the start of printing each time images are printed on a plurality of sheets.
The apparatus described in Japanese Patent Laid-Open No. 2009-241261, however, executes preliminary discharge by moving a printhead to a preliminary discharge acceptable cap, resulting in moving the printhead to execute preliminary discharge each time the images are printed on the plurality of sheets. This poses a technical problem that a time required to complete printing the images on the plurality of sheets prolongs.
The main purpose of executing preliminary discharge immediately before the start of printing is to prevent a discharge failure that may occur due to the fact that ink discharge by a printing operation is not performed while discharging the preceding sheet and feeding the succeeding sheet. Therefore, if it is considered that a time required to discharge the preceding sheet and feed the succeeding sheet is short, and no discharge failure occurs even if ink discharge is not performed during that time, no problem is posed even if preliminary discharge is not executed immediately before the start of printing.
The present invention has been made in consideration of the above-described problems and provides a printing apparatus capable of shortening a time required to complete printing images on a plurality of sheets without causing any discharge failure.
According to the first aspect of the present invention, there is provided a printing apparatus comprising: a maintenance unit configured to execute a maintenance operation between a completion of printing on a preceding sheet serving as the printing sheet fed from a stacking unit first and a start of printing on a succeeding sheet serving as the printing sheet fed from the stacking unit next; and a determination unit configured to determine whether to execute the maintenance operation, wherein the determination unit determines, based on a feeding method of the succeeding sheet, whether to execute the maintenance operation.
According to the second aspect of the present invention, there is provided a printing apparatus comprising: a maintenance unit configured to execute a maintenance operation between a completion of printing on a preceding sheet serving as the printing sheet fed from a stacking unit first and a start of printing on a succeeding sheet serving as the printing sheet fed from the stacking unit next; a determination unit configured to determine whether to execute the maintenance operation; and an estimation unit configured to estimate a non-printing time from the completion of printing on the preceding sheet to the start of printing on the succeeding sheet, wherein the determination unit determines, based on the non-printing time estimated by the estimation unit, whether to execute the maintenance operation.
According to the third aspect of the present invention, there is provided a control method of a printing apparatus comprising: a maintenance step of executing a maintenance operation between a completion of printing on a preceding sheet serving as the printing sheet fed from a stacking unit first and a start of printing on a succeeding sheet serving as the printing sheet fed from the stacking unit next; and a determination step of determining, based on a feeding method of the succeeding sheet, whether to execute the maintenance operation.
According to the fourth aspect of the present invention, there is provided a control method of a printing apparatus comprising: a maintenance step of executing a maintenance operation between a completion of printing on a preceding sheet serving as the printing sheet fed from a stacking unit first and a start of printing on a succeeding sheet serving as the printing sheet fed from the stacking unit next; an estimation step of estimating a non-printing time from the completion of printing on the preceding sheet to the start of printing on the succeeding sheet; and a determination step of determining, based on the non-printing time estimated by the estimation step, whether to execute the maintenance operation.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.
A plurality of printing sheets 1 are stacked on a feeding tray 10 (stacking unit). The top printing sheet 1 stacked on the feeding tray 10 is picked up by a pickup roller 11 and fed toward the downstream side of a sheet conveyance direction by feeding rollers 12. Then, conveyance rollers 14 convey the printing sheet 1 to a position facing a printhead 22, and printing is performed on the printing sheet 1 by discharging ink from the printhead 22. After that, the printing sheet 1 is discharged outside the apparatus by discharge rollers 15.
A platen 16 supports the reverse surface of the printing sheet 1 at the position facing the printhead 22. A carriage 21 is movable in a direction intersecting the sheet conveyance direction (feeding direction) while mounting the printhead 22 thereon. A conveyance guide 13 guides the printing sheet 1 between the feeding rollers 12 and the conveyance rollers 14. A sheet pressing lever 17 can make the leading edge of the succeeding sheet overlap the trailing edge of the preceding sheet.
The controller 31 is connected to various sensors 43 and can obtain sensor signals. The controller 31 is also connected to various encoders 44 and can detect, for example, the position of the carriage 21. The controller 31 is further connected to a motor driver 45 and a head driving circuit 47. The controller 31 drives, by sending a command to the motor driver 45, various motors 46 which operate the pickup roller 11, the feeding rollers 12, the conveyance rollers 14, the discharge rollers 15, the carriage 21, and the like. Also the controller 31 discharges ink from the printhead 22 by sending a command to the head driving circuit 47. The controller 31 can control a printing operation and preliminary discharge (maintenance operation) by combining driving operations of the various motors 46 and ink discharge from the printhead 22.
During the printing operation of a preceding sheet 1a, the pickup roller 11 and the feeding rollers 12 are rotated, thereby moving a succeeding sheet 1b at high speed. This makes it possible to form an overlapping state in which, as shown in ST1 of
The succeeding sheet 1b can be aligned while maintaining the overlapping state as shown in ST2 of
On the other hand, if the type of sheet with high rigidity is designated as the attribute information of the printing image from the host apparatus 42, the trailing end of the preceding sheet 1a and the leading end of the succeeding sheet 1b abut against each other, and the overlapping state may not be formed properly. Therefore, the overlapping state as shown in ST1 of
As shown in ST4 of
On the other hand, as shown in ST1 of
As described above, in this embodiment, the succeeding sheet 1b is fed while forming the overlapping state and preliminary discharge before starting the printing operation of the succeeding sheet 1b is omitted. This makes it possible to shorten the time required from the end of the printing operation of the preceding sheet 1a to the start of the printing operation of the succeeding sheet 1b without causing any discharge failure. It is therefore possible to shorten a time required to complete printing the images on the plurality of sheets.
The second preliminary discharge is also executed for each second time shorter than the first time during the printing operation. The second preliminary discharge is a preliminary discharge operation in which a smaller amount of ink is discharged than in the first preliminary discharge. Executing the second preliminary discharge at a relatively short interval makes it possible to increase the stability of ink discharge in the printing operation. If the first preliminary discharge has been executed during the printing operation, the second preliminary discharge is executed after the second time has elapsed since the first preliminary discharge was executed. That is, the second preliminary discharge is executed each time the second time has elapsed since the first preliminary discharge or the second preliminary discharge was executed last time.
As described above, according to this embodiment, it is possible to shorten the time required to complete printing the images on the plurality of sheets without causing any discharge failure.
The second embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the basic part, i.e. the arrangement of an inkjet printing apparatus, is the same as in the first embodiment, and thus a description thereof will be omitted but only a characteristic arrangement will be described.
In the first embodiment, whether to execute preliminary discharge before starting the printing operation for the succeeding sheet 1b has been determined depending on whether to feed the succeeding sheet 1b while forming the overlapping state between the trailing edge of the preceding sheet 1a and the leading edge of the succeeding sheet 1b. On the other hand, in the second embodiment, a time (to be referred to as a non-printing time hereinafter) required from the end of the printing operation of a preceding sheet 1a to the start of a printing operation for the succeeding sheet 1b is estimated by a method shown in
On the other hand, Lc in
With the above-described La, Lb, and Lc, a non-printing time Tn can be estimated as:
Tn=(La+Lb)×K1+Lc×K2
(where K1 is a coefficient which converts the conveyance amount into a time and K2 is a coefficient which converts the distance into a time).
By comparing the non-printing time Tn with a threshold time Ta in this way, whether to execute preliminary discharge before starting the printing operation for the succeeding sheet 1b is determined.
According to the second embodiment, it is possible to omit preliminary discharge before starting the printing operation of the succeeding sheet 1b depending on the non-printing time irrespective of whether to form the overlapping state between the trailing edge of the preceding sheet 1a and the leading edge of the succeeding sheet 1b.
The third embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the basic part, i.e. the arrangement of an inkjet printing apparatus, is the same as in the first embodiment, and thus a description thereof will be omitted but only a characteristic arrangement will be described.
In the first embodiment, whether to execute preliminary discharge before starting the printing operation for the succeeding sheet 1b has been determined depending on whether to feed the succeeding sheet 1b while forming the overlapping state between the trailing edge of the preceding sheet 1a and the leading edge of the succeeding sheet 1b. On the other hand, in the third embodiment, whether to execute preliminary discharge before starting a printing operation for a succeeding sheet 1b is determined by, in addition to this condition, the positional relationship between a carriage 21 and a cap 23 at the end of a printing operation for a preceding sheet 1a.
If the carriage 21 is close to the cap 23 at the end of the printing operation of the preceding sheet 1a, it does not take time to move the carriage 21 for preliminary discharge. A time required to execute the first preliminary discharge is sufficiently shorter than a time required to feed the succeeding sheet 1b by the method shown in ST1 of
In general, the carriage 21 is away from the cap 23 at the end of the printing operation of the preceding sheet 1a when the final movement of the carriage 21 in the printing operation for the preceding sheet 1a is in the direction away from the cap 23. Therefore, whether the carriage 21 is away from the cap 23 at the end of the printing operation of the preceding sheet 1a may be determined by the final moving direction of the carriage 21 in the printing operation of the preceding sheet 1a. At this time, if the aforementioned moving direction is the direction away from the cap 23, it is determined that the carriage 21 is away from the cap 23 at the end of the printing operation of the preceding sheet 1a. On the other hand, if the moving direction is the direction approaching the cap 23, it is determined that the carriage 21 is close to the cap 23 at the end of the printing operation of the preceding sheet 1a.
According to the execution timings of preliminary discharge during the printing operation shown in
The fourth embodiment of the present invention will be described below with reference to the accompanying drawings. Note that the basic part, i.e. the arrangement of an inkjet printing apparatus, is the same as in the first embodiment, and thus a description thereof will be omitted but only a characteristic arrangement will be described.
In the first embodiment, during the printing operation, the first preliminary discharge has been executed each time the first time has elapsed since the first preliminary discharge was executed last time. On the other hand, in the fourth embodiment, the first preliminary discharge is executed before starting a printing operation for the next printing sheet when the first time has elapsed since the first preliminary discharge was executed last time.
According to the fourth embodiment, the first preliminary discharge which takes relatively long time to execute is executed only before starting the printing operation. It is therefore possible to execute the first preliminary discharge after the elapse of the first time without making hardly any change in a time required to complete printing images on a plurality of sheets.
The feeding method of the succeeding sheet has been described above in the four embodiments. However, the feeding method of the succeeding sheet is not limited to the method described above. An arrangement in which, for example, the feeding method of forming the overlapping state between the trailing edge of the preceding sheet 1a and the leading edge of the succeeding sheet 1b as shown in ST1 of
In the second embodiment, the non-printing time has been estimated by the method shown in
The embodiments have been described above by using the inkjet printing apparatus. However, a printing method is not limited to an inkjet printing method.
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
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 such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2014-166999, filed Aug. 19, 2014, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2014-166999 | Aug 2014 | JP | national |