The present disclosure relates to recording apparatuses and a method for recording.
Japanese Patent Laid-Open No. 2015-147423 discloses a configuration of an ink-jet recording apparatus in which ink is supplied from ink tanks to a recording head through tubes using a water head difference.
Such an ink-jet recording apparatus prevents ink from dripping off by maintaining negative pressure in the recording head using the water head difference to keep a meniscus using surface tension generated in the nozzle of the recording head. The pressure in the recording head is decreased as the ink in the recording head is ejected, thereby charging the ink into the recording head from the ink tanks through the tubes.
The ink in the tubes is acted upon by an inertia force due to the acceleration/deceleration of the recording head which is moving back and forth. In recording an image that needs to eject a lot of ink from the recording head in a short time, the internal pressure of the recording head is significantly decreased with the ejection of the ink. However, since the reciprocating movement of the recording head exerts an inertia force on the ink in the tubes, the recording head may not be sufficiently supplied with ink through the tubes. The supply of insufficient amount of ink causes an ink ejection failure, which affects the quality of the image.
In an aspect of the present disclosure, a recording apparatus includes an ink tank configured to store ink, a recording head including a nozzle that ejects the ink, a carriage having the recording head on board and configured to reciprocate in a first direction and a second direction, an ink supply channel configured to supply the ink from the ink tank to the recording head and having a bend that moves with movement of the carriage, one or more memory devices that store a set of instructions, and one or more processors to execute the set of instructions to perform operations including causing the carriage to move, causing the recording head to eject the ink based on print data to perform recording on a recording medium; and obtaining, based on the print data, information on an amount of ink to be ejected to a recordable area in which the carriage moves in one of the first direction and the second direction, wherein a length of the ink supply channel from the bend to the recording head increases in the first direction and decreases in the second direction, wherein the one or more processors changes acceleration of the carriage according to the amount of ink to be ejected to the recordable area, the amount being indicated by the information.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
An embodiment of the present disclosure will be described hereinbelow with reference to the accompanying drawings.
The ink-jet recording apparatus 1 includes a carriage 2, recording heads 3 held by the carriage 2, ink tanks 4 that store ink, ink supply channels 5 for supplying the ink in the ink tanks 4 to the recording heads 3, a sheet feed tray 15, and a cassette 16. A configuration for feeding, conveying, and discharging sheets incudes a feed roller (not shown), a conveying roller 6, and a sheet discharge roller (not shown).
The image recording operation of the ink-jet recording apparatus 1 will be described. The recording media stacked in the sheet feed tray 15 or the cassette 16 are separated one by one by the feed roller and are fed to the conveying roller 6. The skew of each fed recording medium is corrected by bringing the leading end of the recording medium into abutment against the stopped or reversing conveying roller 6. Then, the recording medium is conveyed to a position where the recording medium faces the recording heads 3 by the conveying roller 6. The recording heads 3 are detachably mounted on the carriage 2. The carriage 2 is supported by guide rails 12 so as to be movable in the direction (X direction) perpendicular to the recording-media conveying direction (Y direction). The carriage 2 moves along the guide rails 12. The recording heads 3 eject ink to the recording medium conveyed to the position facing the recording heads 3 while being moved by the carriage 2 in the X direction to form one band of images on the recording medium. One band (recordable area) is an area in which the recording heads 3 can perform recording by moving in one direction. The recording medium on which one band of images is formed is moved by the conveying roller 6 by a predetermined amount in the +Y direction 1 to form the next one band of images. By repeating the image forming operation and the conveying operation, an image is formed on the entire recording medium. The recording medium on which the image is formed is discharged by the discharge roller.
When the carriage 2 moves from the +X side to the −X side (moves on the backward path), the length L from the bend of the ink supply channel 5 to the connecting portion of the recording head 3 becomes long. Such movement of the carriage 2 causes an inertia force in the ink 9a in the ink supply channel 5 with the length L. This inertia force is generated when the carriage 2 is accelerated and decelerated to move the ink 9a in the ink supply channel 5, thereby causing a dynamic pressure to change the internal pressure of the recording head 3. This embodiment uses this phenomenon to control the acceleration of the carriage 2 at acceleration and deceleration at the reciprocating movement of the carriage 2 to move the ink 9a in the ink supply channel 5 to the recording head 3, thereby reducing a decrease in the pressure in the recording head 3.
An interface (I/F) circuit 410 connects the ink-jet recording apparatus 1 to an external network, such as a local area network (LAN). The ink-jet recording apparatus 1 transmits and receives various jobs and data to and from an external device, such as a host computer, via the I/F circuit 410.
An input/output unit 406 includes an input section and an output section. The input section receives an instruction to turn on the power, an instruction to execute recording, and instructions to set various functions from the user. The output section displays various items of apparatus information, such as a power-saving mode, and setting screens for various functions that can be executed by the ink-jet recording apparatus 1. In this embodiment, the input/output unit 406 is an operation panel provided on the ink-jet recording apparatus 1. The input/output unit 406 is connected to a system bus 416 via the input/output control circuit 405 so as to be capable of transmission and reception of data. In this embodiment, the CPU 401 controls information notification of the output section.
The input section may be the keyboard of the external host computer so that user's instructions can be received from the external host computer. The output section may be a light-emitting diode (LED) display, a liquid crystal display (LCD), or a display connected to the host device. If the input/output unit 406 is a touch panel, user's instructions can be received with a software keyboard. The input/output unit 406 may be a speaker and a microphone to output notification to the user by voice and input user's instruction by voice.
Alternatively, an external information processing apparatus including a CPU and a ROM that have the same functions as those of the CPU 401 and the ROM 402 and connected to the ink-jet recording apparatus 1 may perform a recording-medium determination process (described later) to determine recording media to be used in the ink-jet recording apparatus 1.
A recording-head control circuit 411 supplies a drive signal according to the record data to a nozzle driving circuit mounted on each recording head 3 and including a selector and a switch to control the recording operation of the recording heads 3, such as nozzle drive sequence. For example, when print data is sent from the outside to the I/F circuit 410, the print data is temporarily stored in the RAM 403. The recording-head control circuit 411 drives the recording heads 3 on the basis of record data for recording converted from the print data. At that time, a conveying-motor driving circuit 412 drives a conveying motor 413 on the basis of, for example, the band width of the record data to rotate the conveying roller 6 connected to the conveying motor 413, thereby conveying the recording media. A carriage-motor (CR-MOTOR) driving circuit 414 drives a CR motor 415 to move the carriage 2 along the guide rails 12 with a carriage belt.
The data sent from the I/F circuit 410 includes not only the print data but also data with content that is set by the printer driver. The print data may be received from the outside via the I/F circuit 410 and stored in a storage or may be stored in a storage, such as a hard disk, in advance. The CPU 401 reads the print data from the storage and converts the print data to record data for using the recording head 3 by controlling an image processing circuit 409 (binarizing process). The image processing circuit 409 executes, in addition to the binarizing process, color space conversion, HV conversion, gamma correction, image rotation, and other various image processing operations.
Next, a method for reducing a decrease in the pressure in the recording head 3 by controlling the acceleration of the carriage 2 will be described.
In response to the above, control of the acceleration of the carriage 2 of this embodiment when the amount of the ink 9b ejected for one band of images is large will be described with reference to
The dynamic pressure P1 generated because of the acceleration of the carriage 2 may be adjusted by changing the inside diameter D1 of the tube joints 7 shown in
A processing procedure for the ink-jet recording apparatus 1 of this embodiment using this principle will be described with reference to
First, in step S601, the CPU 401 reads the received print data from the RAM 403.
In step S602, the CPU 401 controls the image processing circuit 409 to execute a process for converting the print data to record data for using the recording head 3 (binarizing process). The CPU 401 counts the amount of ink ejected for each band of the processed print data. Here, the CPU 401 counts the number of ejections (dot number). The CPU 401 temporarily stores the information on the counted dot number in the RAM 403.
In step S603, the CPU 401 controls the feed roller to feed recording media from the sheet feed tray 15 or the cassette 16.
In step S604, the CPU 401 reads the dot count per band calculated in step S602 for the next recording. If it is at the start of recording, the CPU 401 reads the dot count of one band for the first recording.
In step S605, the CPU 401 determines whether the read dot count of the band is greater than a threshold X.
If, in step S605, the CPU 401 determines that the dot count is not greater than the threshold X, the process goes to step S606. If the dot count is equal to or less than the threshold X, the amount of the ink 9b ejected from the recording head 3 is small, and the decrease in the internal pressure of the recording head 3 caused by the recording of the bank is small. For this reason, in step S606, the CPU 401 transmits a signal for controlling the carriage 2 with the profile 1, described in
In contrast, if in step S605 the CPU 401 determines that the dot count is greater than the threshold X, the process goes to step S607. When the dot count is greater than the threshold X, the amount of the ink 9b ejected from the recording head is large, and the decrease in the internal pressure of the recording head 3 due to the recording of the band is small. For this reason, in step S607, the CPU 401 transmits a signal for controlling the carriage 2 with the profile 2, described in
Upon completion of recording of one band, the process goes to step S608, in which the CPU 401 determines whether the next band to be recorded is present. If yes, the process returns to step S605 for processing of the next band. If no, the process ends.
Thus, if the amount of ejection from the recording head 3 is large, the profile for scanning the carriage 2 is changed to move the ink 9a from the ink supply channel 5 to the recording head 3, thereby increasing the internal pressure of the recording head 3.
Repeating this operation for each band prevents the internal pressure of the recording head 3 from decreasing significantly to cause an ejection failure in recording print data that requires a large amount of ink ejected from the recording head 3.
Although the above embodiment moves the carriage 2 with the two profiles, an additional profile may be used.
The carriage 2 is driven with a profile 3 in which the deceleration on the backward path and the acceleration on the forward path are controlled with the absolute value b of acceleration, and the deceleration on the forward path and the acceleration on the backward path are controlled with the absolute value c of the acceleration. With this profile 3, the absolute value of the acceleration of the carriage 2 at the deceleration on the backward path and at the acceleration on the forward path is set to the absolute value b of the acceleration greater than a, and in addition, the absolute value of the acceleration at the deceleration on the forward path and at the acceleration on the backward path is set to the absolute value c of acceleration less than a. This causes, in the area of the absolute value b of acceleration, the ink 9a in the portion of length L in the ink supply channel 5 moves to the recording head 3 because of the inertia force to increase the internal pressure of the recording head 3. Furthermore, in the area of the absolute value c of acceleration, the time from the start of deceleration on the forward path to the end of acceleration on the backward path is increased. During this time, the ink 9a is supplied from the ink tank 4 to the recording head 3 to resolve the decrease in the internal pressure. This allows for reducing the decrease in the internal pressure of the recording head 3 even if the amount of the ink 9b ejected is large.
Although the above embodiment changes the profile for the carriage 2 for each dot count of one image band, as shown in
This embodiment can reduce a decrease in image quality.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure 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 priority from Japanese Patent Application No. 2021-090148, filed May 28, 2021, which is hereby incorporated by reference herein in its entirety.
Number | Date | Country | Kind |
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2021-090148 | May 2021 | JP | national |