Printhead having memory element

• US 5,049,898 A
• Filed: 07/13/1990
• Issued: 09/17/1991
• Est. Priority Date: 03/20/1989
• Status: Expired due to Term

• Current Assignee: Hewlett-Packard Company (HP Inc.)
• Original Assignee: Hewlett-Packard Company (HP Inc.)
• Inventors: Arthur, Alan R., Beeson, Robert R.
• Primary Examiner(s): Hartary, Joseph W.
• Application Number:
  US07/554,102
• Time in Patent Office: 431 Days
• Field of Search: 346/140, 346/139 C, 346/1.1, 400/126, 400/175, 400/703, 400/705.1, 360/1
• US Class Current: 347/19
• CPC Class Codes: B41J 2/17546 electronically
• CPC Class Codes: B41J 2/17553 Outer structure
• CPC Class Codes: B41J 25/34 Bodily-changeable print heads or carriages

Abstract

A disposable printing assembly includes a memory element in which data characterizing the assembly can be stored. This data can characterize the identity of the assembly, or one or more of its operational characteristics. Such operational characteristics for an illustrative ink jet printhead assembly may include the color of ink in the printhead, its amount, or the position of the ink jet orifice plate on the printhead body. This data can then be read from the printhead by a read/write element in a printer and can be used or displayed as desired. The datum characterizing the position of the orifice plate, for example, can be used to controllably delay certain of the firing signals provided to the printhead to compensate for any misalignment. The datum characterizing ink amount can be updated by the write head to reflect use of ink during printing and can warn the user of an impending exhaustion of ink.

Claims

1. In an ink jet printhead that is mounted for movement along a path and wherein the printhead has a housing with an ink chamber therein, a plurality of orifii in fluid communication with the ink chamber, and means for expelling ink from the ink chamber through said orifii, an improvement comprising:

memory means attached to the housing for storing a datum related to an operational characteristic of the printhead; and

data transfer means mounted near the printhead path to read the datum as the printhead moves relative to the data transfer means.

2. The improvement of claim 1 in which the data transfer means is operable for writing data to the memory means as the printhead moves along the path.

3. The improvement of claim 1 in which the memory means comprises a magnetic medium affixed to the outside of said printhead housing.

4. The improvement of claim 3 in which the magnetic medium has a datum stored thereon relating to the color of ink in the chamber.

5. The improvement of claim 1 in which the magnetic medium has a datum stored therein relating to the amount of ink in the chamber.

6. The improvement of claim 1 in which the memory means has a datum stored therein relating to the relative alignment of the printhead'"'"'s orifii and its housing.

7. The improvement of claim 1 in which the memory means has a datum stored therein relating to the operating frequency of the printhead.

8. The improvement of claim 1 in which the memory means has a datum stored therein relating to an attribute of the ink other than its color.

9. In an ink jet printing system having a carriage for carrying an ink jet printhead relative to a printing medium, the carriage including means for orienting the printhead'"'"'s housing in a predetermined orientation in relation thereto, the printhead including a plurality of orifii and means for expelling ink therefrom in response to firing signals, an improvement method comprising the steps:

storing data related to the relative alignment of the printhead'"'"'s orifii and its housing in a memory mounted to the printhead;

retrieving said alignment data from the memory; and

compensating the timing of the firing signals in accordance with said alignment data to reduce the effects of any misalignment between the orifii and the printhead housing.

10. The invention of claim 9 which further includes the steps:

providing the orifii on an orifice plate bonded to the printhead'"'"'s housing;

sensing the position of an alignment feature on the orifice plate; and

storing data relating to said position in the memory.

11. A printer comprising:

a printhead mounted to the printer and operable for movement along a path;

a control circuit coupled to the printhead for controlling the printhead movement and for providing to the printhead operating signals that represent an operational characteristic of the printhead;

a data transfer head mounted to the printer adjacent to the path of the printhead;

a memory element for storing data, the memory element being mounted to the printhead and located to pass near the data transfer head as the printhead moves along the path, the data transfer head being controllable for transferring data to and from the memory element as the element passes the head; and

a monitoring circuit connected between the printhead and the data transfer head, the monitoring circuit receiving and processing the operating signals and controlling the data transfer head to transfer to and from the memory element data that is representative of changes in the operational characteristics of the printhead.

12. The printer of claim 11 wherein the printhead contains a depletable supply of ink and wherein the operating signals represent the amount of ink contained by the printhead, the monitoring circuit controlling the data transfer head to transfer to and from the memory element data representative of the amount of ink contained by the printhead.

13. The printer of claim 12 further comprising indicator means connected to the monitoring circuit for providing an indication signal whenever the ink amount is defected below a predetermined level.