Roll-fed Printer Buffering for UV Curing Speed
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Solution Overview
Problem
Roll-fed printers, especially those using UV curable ink, experience inefficiencies when switching between printing images due to the need for the UV lamp to cure the previous image before starting the next, leading to time loss and challenges in maintaining a close distance between printed images.
Innovation Solution
A method where the print head can start printing the second image while still finishing the last lines of the first image, using a buffer system to transfer image lines from one bitmap to another without interruption, allowing simultaneous printing and curing across swaths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UV lamp cures the previous image before starting the next image, then the curing quality is maintained, but time loss increases between prints
Solution Approach 1:
The patent applies preliminary action by transferring image lines to the buffer in advance before the print head finishes printing. The controller loads image lines for subsequent images into the buffer while the print head is still printing current image lines, so that when the current image is complete, the buffer already contains ready-to-print data. This eliminates waiting time and allows continuous operation without compromising curing quality, as the UV lamp continues curing while the buffer is being populated with next image data.
Solution Approach 2:
The patent implements continuity of useful action by ensuring that the print head never remains idle. While the UV lamp cures the printed image and while image lines are transferred to the buffer, the system continuously prepares the next image data. The buffer acts as a intermediary that maintains continuous data flow to the print head, eliminating interruptions in the printing process and maximizing productivity without sacrificing curing quality.
2Reliability
If the print head waits for the UV lamp to finish curing, then curing completeness is ensured, but printing speed decreases
Solution Approach 1:
The system performs preliminary action by pre-loading image lines into the buffer before the print head completes its current printing task. This allows the print head to immediately begin printing the next image once current image lines are exhausted, without waiting for the UV lamp to finish curing. The curing process continues independently in parallel, maintaining completeness while eliminating idle time for the print head, thus increasing printing speed.
Solution Approach 2:
The patent segments the printing and curing processes into independent parallel operations. The printing function (print head depositing ink) and the curing function (UV lamp hardening ink) are separated in time and space. While the UV lamp cures one image, the print head can prepare and start printing the next image using data already loaded in the buffer. This segmentation allows both processes to proceed simultaneously without interfering with each other, maintaining curing completeness while improving overall printing speed.
3Length of moving object
If the recording medium is transported in reverse direction to maintain close image spacing, then image density increases, but operational complexity increases
Solution Approach 1:
The patent applies continuity of useful action by ensuring the recording medium transports continuously in one direction without reversal. The buffer system allows the print head to print subsequent images immediately as the medium advances, maintaining consistent forward motion. This eliminates the need for reverse transportation to achieve close spacing, simplifying operation while still achieving high image density through continuous printing without idle reversals.
Solution Approach 2:
By pre-loading image data into the buffer in advance, the system enables the print head to continuously print new images as the recording medium advances forward. This preliminary preparation of image data allows close spacing between images to be achieved through continuous forward motion rather than requiring reverse transport, thereby maintaining image density while greatly reducing operational complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach reduces time loss between prints and allows for closer image spacing by enabling the print head to continue printing while the UV lamp cures the previous image, improving overall efficiency and reducing the need for reversing the media transport direction.
Implementation Method 1
UV curable ink is a type of ink that is cured (which comprises, but does not simply consist of, drying) by being subjected to UV radiation of specific wavelengths
Data Source
Figure 1
Figure 2~3
AI summary
The invention provides a roll-fed printing apparatus (100) for printing at least a first and a second image on a recording medium (1), a method for controlling such a printing apparatus (100) and a software medium. According to the method, each swath (42) is printed by a print head (40) that reciprocates in a scanning direction, the print head (40) being controlled to apply marking material to the recording medium (1) in accordance with a first set of image lines for each swath (42) to be printed; the first set of image lines being provided to the print head (40) from a swath buffer (30); wherein the first set of image lines are transmitted to the swath buffer (30) out of a second set of image lines stored in a line buffer (20) to be printed without interruption; wherein, when the line buffer (20) comprises the final image lines of a first bitmap (BM1) representing the first image while there are still empty data storage sections within the line buffer (20) starting image lines of a second bitmap (BM2) representing the second image are transferred to the empty data storage section of the line buffer (20).