Inkjet printing apparatus, control method therefor, and storage medium

Patent metadata

Field	Value
Publication number	US-2022134738-A1
Application number	US-202117512243-A
Country	US
Kind code	A1
Filing date	Oct 27, 2021
Priority date	Oct 30, 2020
Publication date	May 5, 2022
Grant date	—

Abstract

An inkjet printing apparatus includes a print head configured to print an image on a printing medium using a printing element configured to eject ink with thermal energy, a scanning unit configured to cause the print head to scan the printing medium, and a control unit configured to control scanning by the scanning unit and image printing by the print head based on an image printing instruction, wherein the control unit performs a control operation including executing a preliminary ejection to eject, from the print head, ink that does not contribute to image printing before an image is printed in one scanning operation, and determining an amount of ink to be ejected in the preliminary ejection based on a difference between a target temperature and a scanning start temperature, which is a temperature of the print head acquired in response to an instruction to start the one scanning operation.

First claim

What is claimed is:

1 . An inkjet printing apparatus comprising:
a print head configured to print an image on a printing medium using a printing element configured to eject ink with thermal energy; a scanning unit configured to cause the print head to scan the printing medium; and a control unit configured to control scanning by the scanning unit and image printing by the print head based on an image printing instruction, wherein the control unit performs a control operation including: executing a preliminary ejection to eject, from the print head, ink that does not contribute to image printing before an image is printed in one scanning operation; and determining an amount of ink to be ejected in the preliminary ejection based on a difference between a target temperature and a scanning start temperature, the scanning start temperature being a temperature of the print head acquired in response to an instruction to start the one scanning operation.

2 . The inkjet printing apparatus according to claim 1 , wherein in a case where the scanning start temperature is lower than the target temperature, the control unit executes the preliminary ejection depending on the difference between the target temperature and the scanning start temperature.

3 . The inkjet printing apparatus according to claim 2 , wherein in a case where the difference between the target temperature and the scanning start temperature is a first value, the control unit executes the preliminary ejection to eject a first number of ink droplets, and in a case where the difference between the target temperature and the scanning start temperature is a second value greater than the first value, the control unit executes the preliminary ejection to eject a second number of ink droplets, the second number being greater than the first number.

4 . The inkjet printing apparatus according to claim 2 , wherein in a case where the difference between the target temperature and the scanning start temperature is a first value, the control unit executes the preliminary ejection to eject a first amount of ink as a total amount of ink to be ejected, and in a case where the difference between the target temperature and the scanning start temperature is a second value greater than the first value, the control unit executes the preliminary ejection to eject a second amount of ink as the total amount of ink to be ejected, the second amount of ink being larger than the first amount of ink.

5 . The inkjet printing apparatus according to claim 4 , wherein in a case where the difference between the target temperature and the scanning start temperature is the first value, the control unit executes the preliminary ejection at a first frequency, and in a case where the difference between the target temperature and the scanning start temperature is the second value, the control unit executes the preliminary ejection at a second frequency higher than the first frequency.

6 . The inkjet printing apparatus according to claim 4 , wherein in a case where the difference between the target temperature and the scanning start temperature is the first value, the control unit executes the preliminary ejection for a first period of time, and in a case where the difference between the target temperature and the scanning start temperature is the second value, the control unit executes the preliminary ejection for a second period of time longer than the first period of time.

7 . The inkjet printing apparatus according to claim 2 , wherein in a case where the difference between the target temperature and the scanning start temperature is a first value, the control unit executes the preliminary ejection at a first frequency for a first period of time, and in a case where the difference between the target temperature and the scanning start temperature is a second value greater than the first value, the control unit executes the preliminary ejection at a second frequency for the first period of time, the second frequency being higher than the first frequency.

8 . The inkjet printing apparatus according to claim 2 , wherein in a case where the difference between the target temperature and the scanning start temperature is a first value, the control unit executes the preliminary ejection to cause the printing element to generate a first energy in one ejection, and in a case where the difference between the target temperature and the scanning start temperature is a second value greater than the first value, the control unit executes the preliminary ejection to cause the printing element to generate a second energy in one ejection, the second energy being larger than the first energy.

9 . The inkjet printing apparatus according to claim 8 , wherein a length of a driving pulse to be applied to the printing element in a case where the printing element is caused to generate the second energy is longer than a length of a driving pulse to be applied to the printing element in a case where the printing element is caused to generate the first energy.

10 . The inkjet printing apparatus according to claim 1 , wherein the control unit acquires the scanning start temperature during a period from a time when an image printing instruction is input to a time when the preliminary ejection is executed.

11 . The inkjet printing apparatus according to claim 1 , wherein the control unit acquires, as the scanning start temperature, a temperature at a timing when the one scanning operation is started by the scanning unit.

12 . The inkjet printing apparatus according to claim 1 , wherein the control unit executes a heating control for increasing a temperature of the print head in response to an image printing instruction.

13 . The inkjet printing apparatus according to claim 12 , wherein the control unit executes the heating control by causing the printing element to generate thermal energy within a range in which no ink droplets are ejected.

14 . The inkjet printing apparatus according to claim 13 , wherein the control unit suspends the heating control before the one scanning operation is started.

15 . The inkjet printing apparatus according to claim 1 , further comprising a detection unit configured to detect a temperature of the print head,
wherein the control unit acquires the temperature detected by the detection unit as the scanning start temperature.

16 . The inkjet printing apparatus according to claim 1 , further comprising:
a detection unit configured to detect a temperature of the print head; and a storage unit configured to store the temperature detected by the detection unit, wherein the control unit acquires the temperature stored in the storage unit as the scanning start temperature.

17 . The inkjet printing apparatus according to claim 1 , wherein upon detecting that the printing medium is present at a position for image printing in one scanning operation and the scanning unit is located at a scanning start position after scanning prior to the once scanning operation is finished, the control unit controls the scanning unit to start the one scanning operation even in a case where a temperature of the print head is lower than the target temperature.

18 . The inkjet printing apparatus according to claim 1 , further comprising an ink receiver configured to receive ink in the preliminary ejection to eject, from the print head, ink that does not contribute to image printing.

19 . The inkjet printing apparatus according to claim 1 , wherein the control unit executes the preliminary ejection further based on a

Assignees

• Canon Kk

Inventors

• Yokozawa Taku
• Sato Kazuhiko
• Kunimine Noboru
• Murase Takeshi
• Taira Hiroshi
• Kawafuji Hiroshi
• Mogi Sae
• Aichi Akiko

Classifications

• B41J2002/16573

  Cleaning process logic, e.g. for determining type or order of cleaning processes · CPC title

• B41J2002/16564

  Heating means therefor, e.g. for hot melt inks · CPC title

• B41J2/16526 Primary

  by applying pressure only · CPC title

• B41J2/0458

  controlling heads based on heating elements forming bubbles · CPC title

• B41J2/04563 Primary

  detecting head temperature; Ink temperature · CPC title