JP-2026074638-A - Cleaning method and ink ejection device

JP2026074638AJP 2026074638 AJP2026074638 AJP 2026074638AJP-2026074638-A

Abstract

[Problem] To provide an ink ejection device capable of performing cleaning and a method for removing burnt-on residue sufficiently, regardless of the degree of residue buildup. [Solution] A cleaning method for removing burnt residue accumulated on the upper protective layer, comprising a burnt residue removal step in which the upper protective layer is used as the anode electrode and a portion of the upper protective layer that can conduct electricity through the ink is used as the cathode electrode, and a voltage is applied to remove burnt residue accumulated on the surface of the upper protective layer, wherein the burnt residue removal step is performed under a first condition in which a voltage is applied for a first time, and then under a second condition in which a voltage is applied for a second time longer than the first time. [Selection Diagram] Figure 15

Inventors

温井有児
富澤恵二
岩永周三
山本有悟
田中文
石田譲
高瀬光志
石田浩一

Assignees

キヤノン株式会社

Dates

Publication Date: 20260507
Application Date: 20241021

Claims (17)

An electric heat conversion unit is located within the ink channel that communicates with the ink ejection port, An insulating protective layer for blocking contact between the electric heat conversion unit and the ink in the ink channel, The upper protective layer covers the portion of the protective layer that is heated by the electric heat conversion unit, A cleaning method for removing burnt residue accumulated on the upper protective layer of an inkjet head, comprising: The process includes a burnt-on residue removal step in which the upper protective layer is used as the anode electrode, and a portion of the upper protective layer that is electrically conductive through the ink is used as the cathode electrode, and a voltage is applied to remove burnt residue accumulated on the surface of the upper protective layer. The cleaning method is characterized in that the burnt-on residue removal step is performed under a first condition in which a voltage is applied for a first time period, and then under a second condition in which a voltage is applied for a second time period longer than the first time period.
An electric heat conversion unit is located within the ink channel that communicates with the ink ejection port, An insulating protective layer for blocking contact between the electric heat conversion unit and the ink in the ink channel, The upper protective layer covers the portion of the protective layer that is heated by the electric heat conversion unit, A cleaning method for removing burnt residue accumulated on the upper protective layer of an inkjet head, comprising: The process includes a burnt-on grease removal step in which the upper protective layer is used as the anode electrode, and a portion of the upper protective layer that can conduct electricity through the ink is used as the cathode electrode, and a voltage is applied to dissolve the surface of the upper protective layer. The cleaning method is characterized in that the burnt-on residue removal step is performed under first conditions in which a first voltage is applied, and then under second conditions in which a second voltage greater than the first voltage is applied.
An electric heat conversion unit is located within the ink channel that communicates with the ink ejection port, An insulating protective layer for blocking contact between the electric heat conversion unit and the ink in the ink channel, The upper protective layer covers the portion of the protective layer that is heated by the electric heat conversion unit, A cleaning method for removing burnt residue accumulated on the upper protective layer of an inkjet head, comprising: The process includes a burnt-on grease removal step in which the upper protective layer is used as the anode electrode, and a portion of the upper protective layer that can conduct electricity through the ink is used as the cathode electrode, and a voltage is applied to dissolve the surface of the upper protective layer. The cleaning method is characterized in that the burnt-on residue removal step is performed under a first condition in which a pulse that drives the electric heat conversion unit is applied a first number of times, and then performed under a second condition in which the pulse is applied a second number of times, which is fewer than the first number of times.
A cleaning method according to any one of claims 1 to 3, wherein when the number of pulses applied to drive the electric heat conversion unit exceeds a threshold, the conditions for the burnt-on residue removal process are switched from the first condition to the second condition.
The first condition is that a first voltage is applied, The cleaning method according to claim 1 or 3, wherein the second condition is to apply a second voltage greater than the first voltage.
The cleaning method according to claim 1 or 2, wherein the first condition is that the burnt-on charring step is performed each time a pulse for driving the electric heat conversion unit is applied a first number of times, and the second condition is that the burnt-on charring step is performed each time the pulse is applied a second number of times which is less than the first number of times.
The first condition is that the burnt-on charring process is performed by applying a first voltage each time a pulse that drives the electric heat conversion unit is applied a first number of times. The cleaning method according to claim 1, wherein the second condition is that the burnt-on residue removal step is performed by applying a second voltage greater than the first voltage each time the pulse is applied a second number of times, which is fewer than the first number of times.
The cleaning method according to any one of claims 1 to 3, wherein the upper protective layer is made of a material that does not form an oxide film that prevents the dissolution of the upper protective layer by heating of the electrothermal conversion unit.
The cleaning method according to any one of claims 1 to 3, wherein the upper protective layer is formed of a material containing Ir or Ru.
The cleaning method according to claim 1, wherein the first time and the second time are 30 seconds or more and 150 seconds or less.
The cleaning method according to claim 2, wherein the first voltage and the second voltage are 3V or more and 5V or less.
The cleaning method according to claim 3, wherein the first number of times and the second number of times are 2.5 × 10⁸ times or more and 6 × 10⁹ times or less.
The cleaning method according to any one of claims 1 to 3, wherein the electric heat conversion unit is an element that generates energy for ejecting ink from the ejection port.
The cleaning method according to any one of claims 1 to 3, wherein the electrothermal conversion unit is an element that generates pressure for the ink to circulate within the ink channel.
An inkjet head comprising: an ink ejection port for ejecting ink; an electrothermal conversion unit disposed in an ink channel communicating with the ejection port; an insulating protective layer for preventing contact between the electrothermal conversion unit and the ink in the ink channel; and an upper protective layer covering the portion of the protective layer heated by the electrothermal conversion unit. A counting means for counting the number of times a pulse is applied to drive the aforementioned electric heat conversion unit, An identification means for determining whether the number of times the application has been performed is equal to or greater than a threshold, An ink ejection device comprising, The upper protective layer is used as the anode electrode, and the portion that can conduct electricity to the upper protective layer via the ink is used as the cathode electrode, making it possible to dissolve the surface of the upper protective layer by an electrochemical reaction. An ink ejection device characterized by having a changing means for switching the voltage applied for the electrochemical reaction from a first voltage to a second voltage greater than the first voltage when the identification result by the identification means is greater than or equal to a threshold.
An inkjet head comprising: an ink ejection port for ejecting ink; an electrothermal conversion unit disposed in an ink channel communicating with the ejection port; an insulating protective layer for preventing contact between the electrothermal conversion unit and the ink in the ink channel; and an upper protective layer covering the portion of the protective layer heated by the electrothermal conversion unit. A counting means for counting the number of times a pulse is applied to drive the aforementioned electric heat conversion unit, An identification means for determining whether the number of times the application has been performed is equal to or greater than a threshold, An ink ejection device comprising, The upper protective layer is used as the anode electrode, and the portion that can conduct electricity to the upper protective layer via the ink is used as the cathode electrode, making it possible to dissolve the surface of the upper protective layer by an electrochemical reaction. An ink ejection device characterized by having a changing means for switching the time for which voltage is applied for the electrochemical reaction from a first time to a second time that is longer than the first time, when the identification result by the identification means is greater than or equal to a threshold.
An inkjet head comprising: an ink ejection port for ejecting ink; an electrothermal conversion unit disposed in an ink channel communicating with the ejection port; an insulating protective layer for preventing contact between the electrothermal conversion unit and the ink in the ink channel; and an upper protective layer covering the portion of the protective layer heated by the electrothermal conversion unit. A counting means for counting the number of times a pulse is applied to drive the aforementioned electric heat conversion unit, An identification means for determining whether the number of times the application has been performed is equal to or greater than a threshold, An ink ejection device comprising, The upper protective layer is used as the anode electrode, and the portion that can conduct electricity to the upper protective layer via the ink is used as the cathode electrode, making it possible to dissolve the surface of the upper protective layer by an electrochemical reaction. An ink ejection device characterized in that, when the identification result by the identification means is greater than or equal to a threshold, the electrochemical reaction is switched from a first condition in which the reaction is performed each time the pulse is applied a first number of times, to a second condition in which the reaction is performed each time the pulse is applied a second number of times, which is greater than the first number of times.

Description

This disclosure relates to a cleaning method and an ink ejection device. Among the recording methods employed by recording devices such as multifunction printers, the inkjet recording method is a non-impact recording method that enables low noise, high density, and high-speed recording, and is therefore widely adopted. An inkjet ejection unit comprises a mechanism for driving a carrier on which an inkjet head is mounted, a transport mechanism for transporting recording media such as recording paper, and a control configuration for controlling these. In this specification, the inkjet head is also referred to as the "ink ejection head (head)." One method for generating the energy needed to eject ink from the ink ejection head is to heat the ink using an electric heat conversion unit (hereinafter also referred to as "heater") that has a heating resistor, thereby causing foaming. The inks used in ink ejection heads are often dye-based or pigment-based inks. In methods that use an electric heat conversion unit to eject ink, there is a risk of thermal decomposition of the colorant, causing inorganic or organic substances to accumulate on the heater surface, resulting in what is known as "burning." Burning hinders heat conduction from the heater to the ink, leading to a decrease in the ink ejection speed, which can cause problems such as misaligned ink lines, distorted lettering, and color variations. To address this problem, Patent Document 1 proposes a print head having an upper protective layer that is electrically connected to the region including the heating element of the heater, so as to act as an electrode that generates an electrochemical reaction with the ink. In such a print head, the surface of this upper protective layer is used as an anode to dissolve the charred residue that has accumulated along with the metal forming the upper protective layer, thereby removing it through an electrochemical reaction. Japanese Patent Publication No. 2008-105364 Diagram showing the schematic configuration of the recording device.Schematic diagram showing the first circulation path.Schematic diagram showing the second circulation path.Perspective view of the ink ejection headDisassembled perspective view of the ink ejection head.Diagram showing the flow channel component.Diagram showing the connection relationships of flow channels within a flow channel member.Cross-sectional view along the cross-sectional line VIII-VIII in Figure 7Diagram showing the discharge moduleDiagram showing the structure of the recording element substrate.Figure 10 is a perspective view showing the structure of the recording element substrate and lid member along the cross-sectional line XI-XI.Plan view showing a partially enlarged view of the adjacent area of the recording element substrate.Diagram showing the structure of the thermal action area in the recording element substrate.Diagram showing the changes in discharge speed in a conventional example.This diagram shows the change in discharge speed in this embodiment.A diagram modeling the communication between the print head and the main body, and between the ink cartridge and the main body.Flowchart of the recording method including the burnt-on food removal process The embodiments of this disclosure will be described below with reference to the drawings. However, the following description will not unnecessarily limit the scope of this disclosure. The following description illustrates a liquid ejection device having a so-called line-type head with a length corresponding to the width of the recording medium, but the concept of this disclosure can also be applied to a so-called serial-type liquid ejection device that records while scanning the recording medium. A serial-type liquid ejection device configuration might include, for example, one recording element substrate for black ink and one recording element substrate for color ink. However, the configuration is not limited to this; a short line head, shorter than the width of the recording medium, is created by arranging several recording element substrates with overlapping ejection ports in the direction of the ejection port row, and this is scanned across the recording medium. Furthermore, the recording device in this embodiment is a circulating type inkjet recording device that circulates liquid such as ink between a tank and the liquid ejection device, but a non-circulating type configuration is also possible. (First Embodiment) (Inkjet recording device) Figure 1 shows a schematic configuration of a liquid ejection device according to this embodiment, specifically an ink ejection device 1000 (hereinafter also referred to as a recording device) that ejects ink to perform recording. The recording device has a transport unit 1 that transports a recording medium 2 and a line-type ink ejection head 3 arranged substantially perpendicular to the transport direction of the recording medium, and is a line-type device that performs continuous