Prior art

To identify the most relevant prior art for US patent 9512025, I will examine the "Patent Citations" section from the Google Patents entry for US9512025B2. The patent document itself also explicitly mentions and incorporates by reference some prior art.

Here's an analysis of the most relevant prior art cited within US9512025:

Cited U.S. Patents and Applications:

1. US3451798A

• Full Citation: US3451798A, "Sheet glass edge control device"
• Publication Date: June 24, 1969
• Filing Date: April 4, 1966
• Assignee: Corning Glass Works
• Brief Description: This patent describes a device for controlling the edges of sheet glass during its formation. The description within US9512025 explicitly states that "aspects of the present disclosure may be used with forming wedges and edge director configurations as disclosed in U.S. Pat. Nos. 3,451,798, 3,537,834, 7,409,839 and/or U.S. Provisional Pat. Application No. 61/155,669, filed Feb. 26, 2009, each of which are herein incorporated by reference." This indicates that US3451798A is relevant for its teachings on edge director configurations and their use in glass forming.
• Potential Anticipation: US3451798A would likely be considered relevant to the general concept of edge directors in a glass forming apparatus, as covered by elements in claims 1, 8, and 15 that refer to an "edge director intersecting with at least one of the pair of downwardly inclined forming surface portions." It would establish the state of the art regarding edge control devices. However, it would not anticipate the novel aspects of the replaceable heating cartridge with an inclined heat directing surface and its thermal shielding function.

2. US3537834A

• Full Citation: US3537834A, "Method and apparatus for improving thickness uniformity in down drawn glass sheet"
• Publication Date: November 3, 1970
• Filing Date: January 3, 1967
• Assignee: Corning Glass Works
• Brief Description: This patent (also referred to as US3506429A in Google Patents citation, but the patent document explicitly cites 3,537,834) focuses on improving the thickness uniformity of down-drawn glass sheets. As with US3451798A, it's incorporated by reference in US9512025 for its teachings on forming wedges and edge director configurations.
• Potential Anticipation: Similar to US3451798A, this patent would be relevant to the foundational elements of a glass forming apparatus, particularly those pertaining to the forming wedge and edge directors in claims 1, 8, and 15. It would not anticipate the specific heating and shielding features of the replaceable cartridge.

3. US7409839B2

• Full Citation: US7409839B2, "Overflow downdraw glass forming method and apparatus"
• Publication Date: August 12, 2008
• Filing Date: August 8, 2001 (Priority Date for US7681414B2 and US9233869B2 which are related to WO2003055813A1).
• Assignee: Corning Incorporated
• Brief Description: This patent describes a method and apparatus for forming glass using the overflow downdraw process. It is also explicitly incorporated by reference in US9512025 for its forming wedge and edge director configurations.
• Potential Anticipation: This patent would be highly relevant to the overall apparatus and method for forming a glass ribbon using the overflow downdraw process, as described in claims 1 and 15, and the general structure of the forming wedge and edge directors. It likely provides a more modern context for glass manufacturing before the specific innovation of the replaceable heating cartridge in US9512025. It would not anticipate the novel heating cartridge design and its thermal shielding functionality.

4. US Provisional Pat. Application No. 61/155,669

• Full Citation: U.S. Provisional Pat. Application No. 61/155,669
• Filing Date: February 26, 2009
• Brief Description: This provisional application is also incorporated by reference in US9512025 for its teachings on forming wedges and edge director configurations.
• Potential Anticipation: Similar to the other incorporated references, this provisional application would primarily anticipate general aspects of the forming wedge and edge director setup in claims 1, 8, and 15, rather than the specific features of the novel heating cartridge.

5. WO2003055813A1

• Full Citation: WO2003055813A1, "Process for producing sheet glass by the overflow downdraw fusion process"
• Publication Date: July 10, 2003
• Filing Date: December 1, 2000 (Priority Date)
• Assignee: Corning Incorporated
• Brief Description: This international publication describes a process for producing sheet glass by the overflow downdraw fusion process. While not explicitly mentioned in the text of US9512025 as being incorporated by reference, it is listed as a patent citation. This document is relevant for its general teachings on the fusion draw process.
• Potential Anticipation: This reference would be highly relevant to the "flowing molten glass over a pair of downwardly inclined forming surface portions" and "drawing the molten glass from the root" steps in method claim 15. It also provides context for the overall apparatus of claim 1.

Other Examiner-Cited Patents (from Google Patents listing)

While the patent text specifically refers to the patents above for edge director configurations, other patents cited by the examiner on the Google Patents page are also relevant to the broader field of glass manufacturing and heating. Without a detailed analysis of each, it's challenging to determine specific anticipation. However, here are a few more that appear to be highly relevant:

• US3506429A: "Apparatus for improving thickness uniformity in down drawn glass sheet." This patent, also assigned to Corning Glass Works with a priority date of 1967-01-03, addresses aspects of glass sheet uniformity, a common challenge in the field.
• US20010039814A1: "Sheet glass forming apparatus." This application, with a priority date of 2000-05-09, pertains to sheet glass forming apparatus, which would be relevant to the general apparatus claims.
• WO2002044102A1: "Sag control of isopipes used in making sheet glass by the fusion process." This international publication, with a priority date of 2000-12-01, focuses on controlling sag in isopipes, which are integral to fusion draw processes.

The primary innovation of US9512025, as defined in its independent claims, revolves around the replaceable heating cartridge with its inclined heat directing surface that provides thermal shielding to the edge director from the edge rollers, while also directing heat to the edge director. Therefore, any prior art that discloses these specific features in combination would be most relevant for anticipation under 35 U.S.C. § 102. The older patents cited primarily establish the general context of glass forming and edge directors. More recent citations might be more relevant to heating elements, but the specific configuration of the inclined, thermally shielding, and heat-directing cartridge is the distinguishing feature of 9512025.