DETAILED ACTION
Response to Amendment
The Amendment filed 29 April 2026 has been entered. Claims 1-5, and 15-16 remain pending in the application. Claims 6-14 have been withdrawn. No new claim(s) have been added.
Information Disclosure Statement
The information disclosure statement (IDS) submitted on 08 May 2026 was considered by the examiner. The submission is in compliance with the provisions of 37 CFR 1.97.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-5, 15, and 16 are rejected under 35 U.S.C. 103 as being unpatentable over US 2005/0188788 of Ogi in view of JP 2007-084860 of Fujimoto further in view of CN107186218 of Wang.
Claim 1 claims a method of producing a silver powder comprising: a first surface smoothing step of causing fine silver particles having internal voids to mechanically collide with one another; a fine powder removal step of dispersing fine silver particles present after the first surface smoothing step using high-pressure airflow having a supply pressure of not less than 0.2 MPa and not more than 1.0 MPa while removing fine powder; and a second surface smoothing step of causing fine silver particles present after the fine powder removal step to mechanically collide with one another, wherein the first surface smoothing step is performed such that the cumulative power imparted during the first surface smoothing step per 1 kg of the silver powder is not less than 10 Wh/kg and not more than 300 Wh/kg.
Paragraphs [0045-0048] of the instant specification explain how the value for cumulative power imparted of claim 1 is obtained. Applicant describes using a wattmeter to measure the amount of electric power consumed by the motor of the smoothing device. The cumulative power imparted is obtained by integrating by time (summing up over the entire processing time) the power imparted during the smoothing process, Para[0047]. It is also noted that in the instant specification, applicant states that the rotation speed of the rotating blade and the processing time in the first smoothing device should be arbitrarily set such that power is imparted to the silver powder in the way in which it is claimed, Para[0045]. Applicant does not mention specific rotation speeds of the blade. Applicant does, however, disclose different processing times, Para[0074,0079,0081-0086]. Therefore, controlling the cumulative power imparted would require controlling the processing time. This is further supported by the following graph which shows a linear relationship between the processing times and the values for cumulative power imparted disclosed by applicant:
[Chart]
This shows a directly proportional linear relationship between processing time and cumulative power imparted in the instant examples.
Ogi discloses a silver powder and method for producing the same in the same field of endeavor as the claimed invention, that includes surface smoothing by putting silver powder into an apparatus that mechanically causes particles of the silver powder to collide with each other, Para[0027]. Ogi teaches a classification step, preferably an air classification step for separating particles by air flow which removes particles of a desired size, Para[0028]. Ogi also discloses that the input amount of the silver powder, the revolving speed and type of blades of the mixer or mill, and the processing time may be controlled to adjust the fluidization of particles and the smoothing of the shape of the surface due to collision. Ogi teaches that by this surface smoothing process, it is possible to smooth irregularities and angular portions on the surface of particles of the silver powder to decrease the viscosity of a conductive paste using the silver powder without substantially changing the particle diameter and particle size distribution of the silver powder. By this surface smoothing process, it is also possible to greatly improve the sensitivity of a photosensitive paste using the silver powder, Para[0027].
Therefore, based on the teachings of Ogi, it would be obvious to one of ordinary skill in the art to control the processing time, i.e. the amount of time the smoothing device is run, thus controlling the cumulative power imparted on the particle to adequately smooth the shape of the surface of the resulting powder, and thus decreasing the viscosity of the conductive paste.
While the prior art does not specify the numerical limitation for cumulative power imparted recited in claim 1, it is clear applicant’s cumulative power imparted limitation in claim 1 directly relates to the processing time of the smoothing device. Similarly, the prior art discloses equivalent smoothing devices and controlling of the processing time. It therefore is a reasonable conclusion that the resulting material would possess substantially the same physical properties in both instances, see MPEP 2112.01.
Ogi does not teach an airflow pressure or a second surface smoothing step as recited in claim 1.
Wang discloses a preparing method for modified ultrafine noble metal powder in a similar field of endeavor as the claimed invention. Wang teaches airflow pulverization and screening using an air pressure between 0.1 and 1.2 MPa, Para[0032]. This encompassed the claimed range of 0.2 to 1.0 MPa. In the case where the claimed ranges "overlap or lie inside ranges disclosed by the prior art" a prima facie case of obviousness exists, see MPEP 2144.05. Wang discloses that this improves the dispersibility and tap density of the powder, Para[0013].
Fujimoto discloses a method for producing flake silver powder and flake silver powder produced by the method in the same field of endeavor as the claimed invention. Fujimoto teaches a pulverization treatment such that particles collide with each other in order to smooth the surface of the particles, and that the pulverization process can be repeated a plurality of times as necessary, according to the required quality, Para[0031].
Thus, it would be obvious to one of ordinary skill in the art to carry out a first smoothing step with the processing times and removal step disclosed in Ogi under the airflow supply pressure conditions taught in Wang to improve the dispersibility and tap density of the powder. It would also be an obvious variant of the method disclosed in Fujimoto to carry out a second smoothing step following the method set forth in Ogi in order to obtain particles of the required quality.
Therefore, Ogi in view of Fujimoto further in view of Wang reads on all limitations of claim 1.
Claim 2 further limits claim 1 by requiring a coarse powder classification step of removing coarse powder after the second surface smoothing step.
Ogi discloses a classification step for removing large silver particles, Para[0028]. Ogi teaches that any one of such commercially available apparatuses may be suitably chosen in accordance with the desired size of particles to be removed, the particle size distribution of particles after removing agglomerates, the classification speed, the yields of the silver powder and so forth, Para[0028]. Thus, it would be obvious to one of ordinary skill in the art to carry out the classification step disclosed in Ogi after the second surface smoothing step in order to remove the desired size particle. Therefore, Ogi in view of Fujimoto further in view of Wang reads on all limitations of claim 2.
Claim 3 further limits claim 1 by stating that the fine powder removal step includes: a separation and dispersion step of causing the fine silver particles to flow while continuously dispersing the fine silver particles using the high-pressure airflow and separating the fine powder from the fine silver particles; and a fine powder classification step of classifying the fine silver particles that have undergone the separation and dispersion step to remove the fine powder.
Ogi discloses that any number of apparatuses may be used in the classification step, Para[0028], including, for instance, those based on centrifugal force as well as combinations of such apparatuses suggest the use of an apparatus which will cause the silver particles to flow while continuously dispersing them using the airflow. Further the term "classification" implies that one is separating particles of different sizes, the smaller of which can be defined as "fine powder". Thus, Ogi in view of Wang further in view of Fujimoto reads on all limitations of claim 3.
Claim 4 further limits claim 1 by stating that the second surface smoothing step is continued until surfaces of the fine silver particles have an arithmetic average roughness of 3 nm or less in profile roughness measurement.
Fujimoto teaches that the pulverization process can be repeated a plurality of times as necessary, according to the required quality, Para[0031]. Therefore, it would be obvious to one of ordinary skill in the art to conduct the process conducted in Fujimoto until particles of the claimed quality were obtained.
While the prior art does not specify the numerical limitation for average roughness recited in claim 4, the prior art suggests a method involving steps and materials that meet the limitations of the claimed invention. It therefore is a reasonable assumption that the resulting material would possess substantially the same physical properties in both instances, see MPEP 2112.01. Thus, Ogi in view of Fujimoto further in view of Wang reads on all limitations of claim 4.
Claim 5 further limits claim 1 by stating that silver powder present after the second surface smoothing step has an apparent density of 9.8 g/cm3 or less.
Fujimoto teaches that the pulverization process can be repeated a plurality of times as necessary according to the required quality, Para[0031]. Therefore, it would be obvious to one of ordinary skill in the art to conduct the process conducted in Fujimoto until particles of the claimed quality were obtained.
While the prior art does not specify the numerical limitation for apparent density recited in claim 5, the prior art suggests a method involving steps and materials that meet the limitations of the claimed invention. It therefore is a reasonable assumption that the resulting material would possess substantially the same physical properties in both instances, see MPEP 2112.01. Thus, Ogi in view of Fujimoto further in view of Wang reads on all limitations of claim 5.
Claim 15 further limits claim 1 by stating that the second surface smoothing step is continued until surfaces of the fine silver particles have an arithmetic average roughness of 4.9 nm or less in surface roughness measurement of a 500 nm x 500 nm area.
Fujimoto teaches that the pulverization process can be repeated a plurality of times as necessary according to the required quality, Para[0031]. Therefore, it would be obvious to one of ordinary skill in the art to conduct the process conducted in Fujimoto until particles of the claimed quality were obtained.
While the prior art does not specify the numerical limitation for average roughness recited in claim 15, the prior art suggests a method involving steps and materials that meet the limitations of the claimed invention. It therefore is a reasonable assumption that the resulting material would possess substantially the same physical properties in both instances, see MPEP 2112.01. Thus, Ogi in view of Fujimoto further in view of Wang reads on all limitations of claim 15.
Claim 16 further limits claim 1 by stating that the second surface smoothing step is performed such that the cumulative power imparted during the second surface smoothing step per 1 kg of the silver powder is 60 Wh/kg or more.
Fujimoto teaches that the pulverization process can be repeated a plurality of times as necessary according to the required quality, Para[0031]. Therefore, it would be obvious to one of ordinary skill in the art to conduct the process conducted in Fujimoto until particles of the claimed quality were obtained.
While the prior art does not specify the numerical limitation for cumulative power imparted recited in claim 16, the prior art suggests a method involving steps and materials that meet the limitations of the claimed invention. It therefore is a reasonable assumption that the resulting material would possess substantially the same physical properties in both instances, see MPEP 2112.01. Thus, Ogi in view of Fujimot further in view of Wang reads on all limitations of claim 16.
Response to Arguments
Applicant's arguments filed 29 April 2026 have been fully considered but they are not persuasive. Applicant argues that (remarks, page 9 of 12) Fujimoto fails to cure the defect of Ogi since Fujimoto is silent on the above-mentioned specific cumulative power range imparted in the first surface smoothing step recited in claim 1, and in the second surface smoothing step recited in claim 16. This is not found persuasive as primary reference Ogi teaches that the processing time may be controlled to optimize the fluidization of particles and the smoothing of the shape of the surface due to collision, Para[0027]. Ogi’s teachings of the controlling of the processing time meet the limitations of claim 1 as the cumulative power imparted is directly proportional to the processing time of applicants claimed invention as explained in the 103 rejection of claim 1 above.
Applicant argues that (remarks, page 8 of 12) the claimed method achieves unexpected results because the tap density of example 1, in which two smoothing steps were performed is greater than the tap density of comparative example 2 in which only one smoothing step was performed. This is not found persuasive as Fujimoto discloses performing multiple steps.
Additionally, Applicant argues that (remarks, page 8 of 12) an advantageous effect of improving tap density by limiting the cumulative power imparted during the first smoothing step is a result of the claimed method inhibiting the generation of fine scraps during the first step which could act as “glue” linking the particles promoting the formation of agglomerates. This phenomenon of increased particle connection with increasing processing time is disclosed by Fujimoto. Fujimoto teaches that when a long processing time is employed, the flaked particles are easily connected to each other, and the frequency of occurrence of coarse particles increases, Para[0038]. Therefore, one of ordinary skill in the art would be able to consider Fujimoto’s teaching of increased particle connection with increased processing time and reasonable expect the tap density results of example 1 and comparative example 2.
Thus, the rejection is maintained.
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
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/Keith D. Hendricks/Supervisory Patent Examiner, Art Unit 1733
/JACOB BENJAMIN STILES/ Examiner, Art Unit 1733
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