Patent Application
20250074090
The present invention relates to a printing apparatus.
There is known a printing apparatus that prints an image by discharging ink from a printhead. In a printing apparatus including a plurality of printheads, there may be a printhead that need not discharge ink depending on an image to be printed or print settings. Japanese Patent Laid-Open No. 2002-59559 discloses a technique of moving color heads that need not discharge ink to a maintenance position when monochrome printing is selected.
In the technique of Japanese Patent Laid-Open No. 2002-59559, if color printing is selected, the color heads standby at a printing position. The color heads include a yellow head, a magenta head, and a cyan head. For example, even if cyan ink need not be discharged, the cyan head is made to stand by at the printing position. For this reason, the printing performance of the cyan head may be lowered.
The present invention provides a technique of preventing the printing performance of each printhead from lowering.
According to the present invention, there is provided a printing apparatus comprising: a moving unit configured to individually move a plurality of printheads provided for types of liquids between a printing position at which a liquid is discharged to a print medium and a retracted position retracted from the print medium as compared to the printing position; a conveying unit configured to convey the print medium; and a control unit configured to control the moving unit such that a printhead that discharges a liquid of a type to be used for printing among the plurality of printheads is located at the printing position, and a printhead that discharges a liquid of a type not to be used for printing is located at the retracted position, wherein the control unit controls the moving unit to move a printhead of a moving target during conveyance of the print medium.
Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
Hereinafter, embodiments will be described in detail with reference to the attached drawings. Note, the following embodiments are not intended to limit the scope of the claimed invention. Multiple features are described in the embodiments, but limitation is not made to an invention that requires all such features, and multiple such features may be combined as appropriate. Furthermore, in the attached drawings, the same reference numerals are given to the same or similar configurations, and redundant description thereof is omitted.
The printing apparatus 1 includes a feeding device 104, an image forming device 100, and a discharge device 105. In this embodiment, a continuous sheet (roll sheet) is used as the print medium P. The print medium P is sent from the feeding device 104 to the discharge device 105 via the image forming device 100. Note that the present invention is also applicable to a printing apparatus that prints an image on a cut sheet.
The feeding device 104 is a device that supplies the print medium P that is a roll sheet to the image forming device 100. The feeding device 104 pulls out the print medium P by rotating the rolled print medium P about a rotating shaft 117 and feeds the print medium P to the image forming device 100 at a predetermined speed via a plurality of conveyance rollers 104a. The print medium P is conveyed from the feeding device 104 to the image forming device 100 and the discharge device 105 in this order.
The discharge device 105 is a device that discharges, from the image forming device 100, the print medium P that is a product with a printed image. The discharge device 105 conveys the print medium P, which is conveyed from the image forming device 100, at a predetermined speed via a plurality of conveyance rollers 105a. The print medium P that is a product is wound in a roll by a rotating shaft 118 that rotates.
The image forming device 100 includes an additional printing device 115 and a preprinting device 116. A conveying device 101 includes a plurality of conveyance rollers 101a, and conveys the print medium P, which is fed from the feeding device 104, at a predetermined speed such that it passes through the preprinting device 116 and the additional printing device 115 in this order.
The preprinting device 116 performs spot color printing as preprinting. In spot color printing, for example, a base with a predetermined pattern is printed. The additional printing device 115 performs printing of basic colors as additional printing. In printing of basic colors, for example, a predetermined pattern is the like is printed. That is, it can be said that the printing apparatus 1 is a digital printing apparatus that performs preprinting and additional printing.
The preprinting device 116 includes a skew correction unit 110, a printing unit PT1, a drying unit 112, and a cooling unit 113, which are arranged sequentially from the upstream side in the conveyance direction of the print medium P. The skew correction unit 110 corrects skew of the print medium P.
The printing unit PT1 includes a printhead 2WP, a printhead 2W, and a moving unit 3A. In this embodiment, the printhead 2W discharges white ink, and the printhead 2WP discharges primer ink for fixing. The printhead 2WP is located on the upstream side in the conveyance direction of the print medium P with respect to the printhead 2W. The moving unit 3A is a mechanism that moves the printhead 2WP and the printhead 2W individually between a printing position and a retracted position. The drying unit 112 heats the print medium P, thereby promoting drying of ink discharged to the print medium P. The cooling unit 113 cools the print medium P heated by the drying unit 112.
The additional printing device 115 includes a printing unit PT2, a drying unit 106, a cooling unit 108, and an inspection unit 107, which are arranged sequentially from the upstream side in the conveyance direction of the print medium P.
The printing unit PT2 includes a printhead 2P, a printhead 2B, a printhead 2Y, a printhead 2M, and a printhead 2C, which are arranged sequentially from the upstream side in the conveyance direction of the print medium P. In this embodiment, the printhead 2P discharges primer ink for fixing. The printhead 2B discharges black ink. The printhead 2Y discharges yellow ink. The printhead 2M discharges magenta ink. The printhead 2C discharges cyan ink. Also, the printing unit PT2 includes a moving unit 3B. The moving unit 3B is a mechanism that moves the printhead 2P, the printhead 2B, the printhead 2Y, the printhead 2M, and the printhead 2C individually between a printing position and a retracted position.
Note that when generally referring to the printheads 2WP, 2W, 2P, 2B, 2Y, 2M, and 2C or indicating an arbitrary printhead, it is sometimes called a printhead 2. When generally referring to the moving units 3A and 3B or indicating an arbitrary moving unit, it is sometimes called a moving unit 3.
The drying unit 106 heats the print medium P, thereby promoting drying of ink discharged to the print medium P. The cooling unit 108 cools the print medium P heated by the drying unit 106. The inspection unit 107 is a device that reads and inspects the image printed on the print medium P and includes, for example, a scanner device. Examples of inspection contents are inspection of color misalignment of the printed image, inspection of discharge failures of the printhead 2, and inspection of the tint of the printed image. These inspections may be performed by printing a test pattern on the print medium P by the printhead 2 and reading the test pattern by the inspection unit 107.
The printing apparatus 1 also includes an operation unit 401 and a control unit 402. The operation unit 401 accepts a user instruction. The control unit 402 is an electronic circuit (for example, a personal computer) that controls the printing apparatus 1.
The printhead 2 and the moving unit 3 will be described. The printhead 2 according to this embodiment is a full-line head and can discharge ink supplied from an ink tank (not shown) to the whole region of the print medium P in the widthwise direction. One printhead 2 discharges one type of ink. For example, the printhead 2B discharges only black ink. The preprinting device 116 is provided with two printheads, and the additional printing device 115 is provided with five printheads. That is, a total of seven printheads are provided. When printing basic colors, four or more printheads 2 (cyan, magenta, yellow, and black) suffice.
In the apparatus including the plurality of printheads 2, depending on the image to be printed, the printheads 2 that discharge ink and the printheads 2 that do not may occur during the printing operation. Vapor of water of the ink floats on the print medium P. If the vapor sticks to the printhead 2 that does not discharge ink, the printing performance thereof may lower. To prevent this, in this embodiment, the printheads 2 can be moved between the printing position and the retracted position by the moving unit 3.
The moving unit 3B includes moving mechanisms 30P, 30B, 30Y, 30M, and 30C for the printheads 2. The moving mechanism 30P moves the printhead 2P. The moving mechanism 30B moves the printhead 2B. The moving mechanism 30Y moves the printhead 2Y. The moving mechanism 30M moves the printhead 2M. The moving mechanism 30C moves the printhead 2C. The moving mechanisms 30P, 30B, 30Y, 30M, and 30C each include a driving source 31 such as a motor, and an actuating mechanism 32 that moves the printhead 2 by the driving force of the driving source 31. The actuating mechanism 32 is, for example, a ball screw mechanism, a belt transmission mechanism, a link mechanism, or the like. In this embodiment, the actuating mechanism 32 raises/lowers the printhead 2 between the printing position on the lower side and the retracted position on the upper side.
The moving unit 3B is controlled to locate each printhead 2 that discharges ink to be used for printing at the printing position and each printhead 2 that discharges ink not to be used for printing at the retracted position, thereby performing a printing operation. When vapor is prevented from sticking to the printhead 2 that discharges ink not to be used for printing, the printing performance can be prevented from lowering. Note that although the printing unit PT2 is exemplarily shown in
A communication device 403 is formed by, for example, a communication control device such as a local area network (LAN) card. The communication device 403 receives a print job from, for example, an external device (for example, a user terminal), and the control unit 402 executes printing of the received print job.
A storage device 404 is an external storage device of the control unit 402, and is formed by, for example, a nonvolatile semiconductor memory (so-called flash memory), a hard disk drive (HDD), or the like. The storage device 404 can store various kinds of programs to be executed by the control unit 402 and various kinds of data necessary for execution of these programs.
The operation unit 401 is, for example, a touch panel, and includes a display device such as a liquid crystal display, and an input device that recognizes a touch operation. The display device displays various kinds of information on a display screen in accordance with a display control signal transmitted from the control unit 402. The input device accepts various kinds of input operations by the user via various kinds of operation keys such as buttons displayed on the display device, and transmits an operation signal to the control unit 402. The operation unit 401 is used, for example, by the user to set job information when executing a print job.
The procedure of processing of the printing apparatus 1 will be described. The print medium P is sent from the feeding device 104 to the discharge device 105 via the image forming device 100 in advance. The user creates preprint data (base data) and additional print data of a print job on, for example, the external device and sets printing conditions, thereby creating a print job. The print job is then transmitted to the control unit 402 via a communication network. If the user performs a start operation on the operation unit 401, the printing operation is started. The print medium P is conveyed at a predetermined speed, and ink is discharged from the printheads 2 onto the print medium P to print an image.
Movement control of the printheads 2 by the moving unit 3 will be described. In this embodiment, the moving schedule of the printheads 2 is generated in advance, and after the start of the printing operation, the printheads 2 as the moving target are moved in accordance with the moving schedule.
In step S1, rasterization processing of print data of a received print job is executed. The print data in the PDF format is thus converted into print data in the raster file format. In step S2, image processing is performed for the print data in the raster file format, and data for each type of ink is generated on a page basis.
Based on the data for each type of ink generated in step S2, it is possible to specify types of inks to be used or not to be used. Note that specifying at least one of ink to be used and ink not to be used suffices. In step S3, based on the data generated in step S2, the types of inks to be used for printing and the types of inks not to be used for printing are specified for each page.
Note that the presence/absence of use of primer ink is not shown in
In step S4 of
For example, assume that the length of each page of print data on the conveyance direction of the print medium P is 300 mm. The conveyance amount of the print medium P is 0.3 m in the first page, 0.6 m in the second page, 0.9 m in the third page, and 1.2 m in the fourth page. Images of about 333 pages are printed in the printing section of 100 m. If the total number of pages of the print data is 1,400, the total conveyance distance of the print medium P is 420 m.
In the processing of step S4, first, based on the information shown in
In the processing of step S4, next, a moving schedule is generated based on the specifying result shown in
The moving schedule indicates timing of moving the printhead 2 during conveyance of the print medium P with respect to the time from the start of the printing operation as a reference. In the example shown in
In this embodiment, the printhead 2 that discharges a type of ink to be used for printing in a certain printing section is located at the printing position at the start of the printing section. The printhead 2 that discharges a type of ink not to be used for printing in a certain printing section is located at the retracted position after the start of the printing section.
The contents of
Next, according to the example shown in
Next, according to the example shown in
The moving schedule is generated in this way. The created moving schedule is stored in the storage device 404.
In step S11, it is determined whether the moving timing of any printhead 2 has arrived. If there is the printhead 2 whose moving timing has arrived, the process advances to step S12. If such a printhead does not exist, the processing is ended. In step S12, moving processing is executed. Here, the moving unit 3 is controlled to move the printhead 2 whose moving timing has arrived to the printing position or the retracted position. The processing is thus ended.
Note that in this embodiment, the moving schedule from the first page to the last page is generated at once before the start of the printing operation. However, the moving schedule may be created while performing the printing operation. For example, a moving schedule corresponding to the printing section from 0 to 200 m may be generated first. The printing operation is started, and a moving schedule corresponding to the next printing section from 200 to 300 m may be generated before the printing section from 1 to 100 m ends.
Also, in this embodiment, the moving schedule is created after the specifying processing of step S3 is performed for all pages. However, these processes may be executed in parallel. In this case, the specifying processing of step S3 may not be performed for all pages. For example, if using all types of inks in the printing section from 0 to 100 m is defined in a section from 1 to 10 m, the specifying processing of step S3 can be omitted for pages corresponding to the remaining section from 10 to 100 m.
In the first embodiment, the unit length of the printing section is 100 m. The unit length may be changed in accordance with the conveyance speed of a print medium P. For example, if the conveyance speed is 10 mpm, the unit length may be 25 m. In addition, the length may be changed in accordance with the printing section. For example, the first printing section may be from 0 to 80 m, and the next printing section may be from 80 to 200 m.
The shortest distance of the printing section can be set in consideration of the moving time of a printhead 2. For example, if the time of moving the printhead 2 from the printing position to the retracted position is 20 sec, and the time of moving the printhead 2 from the retracted position to the printing position is also 20 sec, a time of 40 sec is necessary to move from the printing position to the retracted position and return to the printing position again. Hence, the distance in which the print medium P can be conveyed in 40 sec can be the shortest distance of the printing section.
Also, the printing section may be set for each type of ink. For example, for cyan ink, the first printing section may be from 0 to 80 m, and for magenta ink, the first printing section may be from 0 to 120 m.
An example of handling a case where a page is located across printing sections will be described. In the first embodiment, an example in which the length of each page in the conveyance direction of the print medium P is 300 mm, and the unit length of the printing section is 100 m has been described. In this case, images of about 333 pages are printed in the printing section of 100 m, and the image of the 334th page is located across the printing section from 0 to 100 m and the printing section from 100 to 200 m.
Here, assume that yellow ink is needed to print the image of the 334th page, and there is no other image uses yellow ink in the printing section from 100to 200 m. In this case, the timing of moving the printhead 2Y that discharges yellow ink to the retracted position may be delayed to timing after printing of the image of the 334th page.
Also, assume that yellow ink is needed to print the image of the 334th page, the yellow ink is needed in the printing section from 100 to 200 m as well, and there is no other image that uses yellow ink in the printing section from 0 to 100 m. In this case, the timing of moving the printhead 2Y that discharges yellow ink to the printing position may be advanced to timing before printing of the image of the 334th page.
Also, if there is a page located across the printing sections, the movement of the printhead 2 may be delayed or advanced uniformly by an amount corresponding to the page without confirming ink used in the page.
When repetitively printing the same print data, a moving schedule may be generated using information created at the time of first printing of the print data. This can shorten the processing time and reduce the operation load.
In step S21, the presence/absence of storage is confirmed with the user. For example, display for inquiring about the presence/absence of storage is done on an operation unit 401. If the user selects storage, the process advances to step S22. In step S22, the result (information shown in
It is also possible to use a moving schedule generated in the past.
In step S41, the presence/absence of storage is confirmed with the user. For example, display for inquiring about the presence/absence of storage is done on the operation unit 401. If the user selects storage, the process advances to step S42. In step S42, a moving schedule generated in step S4 of
Note that in the examples shown in
If time of keeping a printhead 2 located at the retracted position is long, nozzles may dry, and ink discharge performance may be low. To prevent this, if the printhead 2 is moved from the retracted position to the printing position, preliminary discharge of the printhead 2 may be performed.
The example shown in
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. 2023-141558, filed Aug. 31, 2023, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2023-141558 | Aug 2023 | JP | national |
